The Buffy the Vampire Slayer alum and She's All That actor met on the set of the 1997 horror film I Know What You Did Last Summer. However, it wasn't until a few years later, after an accidental date, that the former costars became more than friends.
Although neither of them "were into marriage" nor believed in it, Prinze told PEOPLE Now in 2020 that "one day, I just knew we were gonna get married and I knew I was gonna propose. I didn't know when or how. And so I did and fortunately, she was on the same page. My instincts were correct."
Gellar added, "I think for the first time it felt different right. Maybe it was the right time for both of us in our lives."
The Scooby-Doo costars went on to tie the knot in 2002 at a resort in Mexico. "We are each other's best friend," Gellar said at the time. "He is my first love."
Gellar has credited their long-lasting marriage to being mindful and present with each other. "Take the 10 minutes – put the phone down. Have a cup of coffee together. Walk the dog at the end of the night. Read a story with your kids," she once told PEOPLE. "Make the most of the time that you have. We are all pulled in so many directions, so make sure that, whichever one you are focusing on, you're present."
From costars to husband and wife, here is a complete timeline of Sarah Michelle Gellar and Freddie Prinze Jr.'s relationship.
1997: Sarah Michelle Gellar and Freddie Prinze Jr. meet
However, things changed once the pair got to know each other more. "Then one day I gave her a ride to the gym. We talked on the way up, and she was a cool chick," Prinze said.
1999: Sarah Michelle Gellar makes a cameo in Freddie Prinze Jr.'s movie She's All That
Gellar made a brief cameo in her future husband's iconic 1999 rom-com She's All That. As director Robert Iscove told Cosmopolitan in 2015, "[Gellar] was there visiting Freddie and we asked her if she would come and do it, and she said she would come and do it, but she wouldn't speak. She wouldn't say any lines. Okay, we don't know why you wouldn't say, 'Thank you,' or 'No.' But that was her thing and she did it. And to get Buffy in the movie was certainly [a big deal] — because at that point, Buffy was huge."
In a 2021 Instagram post, Gellar reflected on her cameo, jokingly writing, "In honor of its 22 anniversary, I thought I would post one of my greatest on-screen performances in #shesallthat. I think you really understood that my character did not want pepper. Also, I believe my husband @realfreddieprinze made an appearance in that film as well 😂 😂 #flashbackfriday #fbf #anniversary."
January 2000: Sarah Michelle Gellar and Freddie Prinze Jr. go on their first date
The two actors were friends for a while before going on their first date together, and that date was actually an accident. "We were friends for a very long time. We'd had many dinners before. And we were supposed to go with someone else, and the third person didn't make it out and we decided to still go," the Buffy star recalled to PEOPLE Now in 2020.
"We were just two people at dinner catching up," she added. "We had a long car ride and a long dinner and things just happened."
Prinze noted that after their first date, "I didn't go on dates with other girls, nor did I even want to pursue dates with other girls."
April 2001: Sarah Michelle Gellar and Freddie Prinze Jr. get engaged
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Less than two years after their friendship turned romantic, Gellar and Prinze got engaged. According to ABC News, they reportedly announced their engagement at a party for the actress's 24th birthday.
June 2002: Sarah Michelle Gellar and Freddie Prinze Jr. attend the premiere of Scooby-Doo
Prinze and Gellar shared the screen once again, playing Fred Jones and Daphne Blake in the live-action film Scooby-Doo. The couple walked the red carpet together at the premiere in coordinating outfits.
September 1, 2002: Sarah Michelle Gellar and Freddie Prinze Jr. get married
Sarah Michelle Gellar Instagram
In September 2002, Gellar and Prinze exchanged vows in Mexico at the El Careyes resort. The bride wore a strapless Vera Wang gown for her big day, while the groom was dressed in a linen Sy Devor suit. Celebrity guests at the couple's wedding included Shannen Doherty and Wilmer Valderrama.
"They glowed as they gazed at one another," said a guest. "Everyone could feel the love they were sharing. It was perfect."
March 20, 2004: Sarah Michelle Gellar and Freddie Prinze Jr. attend the premiere of Scooby-Doo 2
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The married pair reprised their roles as Daphne and Fred in the 2004 film Scooby-Doo 2: Monsters Unleashed. Gellar was all smiles as Prinze wrapped his arm around her while posing for photos at the Hollywood premiere of the sequel.
April 9, 2009: Sarah Michelle Gellar and Freddie Prinze Jr. are expecting their first baby
A source close to the couple confirmed to PEOPLE that Gellar and Prinze were expecting their first baby together. "They're very excited," the source said.
September 19, 2009: Sarah Michelle Gellar and Freddie Prinze Jr. welcome their first baby
Gellar and Prinze became first-time parents in 2009. The pair's daughter, Charlotte Grace Prinze, was born on Sept. 19. A rep for the actress told PEOPLE at the time, "The family is over the moon."
November 6, 2009: Sarah Michelle Gellar and Freddie Prinze Jr. open up about parenthood
In an interview with PEOPLE, the new parents revealed why they waited several years after getting married to have kids. "Becoming a parent is the most selfless act, and you need to be at a point in your life where you can give up anything and everything for a child," Gellar explained. "I don't know if you know how to do that when you're in your 20s."
Prinze shared similar sentiments, saying, "I'm so happy we didn't have kids in our 20s — I just didn't know a thing. You have so much more patience in your 30s, and I feel like I appreciate this so much more."
April 26, 2012: Sarah Michelle Gellar and Freddie Prinze Jr. reveal they are expecting their second child
PEOPLE confirmed in April 2012 that the couple had a second baby on the way. "She and Freddie are thrilled," a source close to Gellar revealed. "They love their little girl more than anything in the world and know that love will only multiply. She is such a fantastic mom; it is just great news."
September 20, 2012: Sarah Michelle Gellar and Freddie Prinze Jr. welcome a son
The couple's family grew by one with the arrival of their son, Rocky James Prinze.
In a touching Instagram tribute to commemorate Rocky's 7th birthday in 2019, Gellar wrote, "And just when I thought it wasn't possible to love another human the way I loved my daughter, seven years ago today, my son was born, and I learned that was not the case. Rocky, on the day you were born, I swear my heart tripled in size. Your laugh is the only medicine I will ever need, and your excitement for life is my motivation."
September 1, 2017: Sarah Michelle Gellar and Freddie Prinze Jr. celebrate their 15th wedding anniversary
Gellar and Prinze celebrated 15 years of marriage in 2017. Sharing a video montage featuring photos of her and Prinze throughout the years, the mom of two wrote: "My husband thinks I'm crazy, but I'm not the one who married me. #happyanniversary @realfreddieprinze 15 years!!"
February 14, 2019: Sarah Michelle Gellar calls Freddie Prinze Jr. her "personal Google"
On Valentine's Day 2019, Gellar gave her husband a special shout-out on Instagram and called him her "personal Google." Alongside a black-and-white selfie of the two of them, the actress penned, "Happy #valentines@realfreddieprinze You are my own personal Google...everything I'm searching for. #valentinesday."
November 22, 2019: Freddie Prinze Jr. says he and Sarah Michelle Gellar are "so night and day"
Prinze told PEOPLE ahead of Thanksgiving 2019 that he and his wife couldn't be more different, proving the theory that opposites attract.
"Sarah and I are so night and day, and it's why we've always been a good couple and had a good relationship, because everything I don't enjoy she's really good at, and everything she really doesn't enjoy I'm really good at," he said. "It's never a hassle for me to cook dinner because I like it."
The father of two also shared how his family prepares for Thanksgiving. "My daughter is very involved in the process," he explained. "She makes a side dish, at least one, every year. My son just eats. It works out! But she really has a joy for it, a love for it, and she asks all the time — even if I don't want her help, she's helping."
January 31, 2020: Sarah Michelle Gellar marks the 20th anniversary of her and Freddie Prinze Jr.'s first date
Gellar didn't let the 20th anniversary of her and Prinze's accidental first date go by without a tribute on Instagram. "20 years ago this week, my friend @realfreddieprinze and I were supposed to have dinner with a mutual friend from out of town. That friend missed her flight, but we decided to still meet and catch up," she wrote in 2020. "Now 20 years together, 17 plus married and two kids, we still go to that restaurant for dinner. So thank you @sloaney77 for not showing up for dinner."
February 2020: Sarah Michelle Gellar and Freddie Prinze Jr. reveal their family rules
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In a February 2020 interview with PEOPLE, Gellar and Prinze discussed their "no phones at the dinner table" rule, which they enforced in an effort to be more present with each other.
"It's our marriage and we just try to stay in the moment," Prinze said.
Gellar added, "It's about making sure that eye contact is made and that conversations are had."
The Summer Catch actor also noted at the time that their kids didn't have phones yet. "That's a grown-up rule!" he said.
December 2020: Sarah Michelle Gellar and Freddie Prinze Jr. expand their family
Gellar and Prinze welcomed two new additions to their family in 2020 — twin Akita puppies. The actress introduced the adorable pups on Instagram, writing, "Welcome to the family Kumi and Sato (they are 8-week-old Akita twins). Be prepared for lots of doggie spam from me because they are beyond cute (and also because I won't be going anywhere for a while) 🐶 #akita#akitasofinstagram."
October 31, 2021: Sarah Michelle Gellar and Freddie Prinze Jr. dress as the Dirty Dancing couple for Halloween
The pair channeled Dirty Dancing's Baby and Johnny for Halloween 2021. "Nobody puts baby in the corner #happyhalloween from Baby Houseman and Johnny Castle #dirtydancing#loverboy," Gellar captioned photos of the two of them dressed in costume.
March 8, 2022: Sarah Michelle Gellar says Freddie Prinze Jr. is a "champion and friend to women"
Sarah Michelle Gellar Instagram
Gellar opted against making a joke to commemorate her husband's 46th birthday in 2022. Sharing a photo of herself with Prinze in addition to a snapshot of him and a dessert, the actress instead wrote, "Today is @realfreddieprinze birthday. Normally, this is where I would make a joke. But it's also #internationalwomensday and it completely makes sense that you share that day, as there is no man that is a bigger champion and friend to women than you."
She added, "I couldn't think of someone better to raise a daughter with or to teach a son, what it truly means to be a good man. Happy birthday FP."
May 22, 2022: Sarah Michelle Gellar and Freddie Prinze Jr. attend their kids' weekend activities
Sarah Michelle Gellar Instagram
Gellar and Prinze's celebrity status has never deterred them from showing up to their kids' sports games and dance recitals. In May 2022, the couple were on hand for their children's weekend activities. Gellar captioned a selfie of her and Prinze sitting on the sidelines, "Mom and Dad assuming the weekend positions #footballmom #basketballmom #dancemom."
September 1, 2022: Sarah Michelle Gellar and Freddie Prinze Jr. celebrate 20 years of marriage
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In September 2022, the couple rang in two decades of marriage. To celebrate the impressive feat, Gellar and Prinze both posted tributes to one another on Instagram and shared photos from their 2002 wedding day.
On her Instagram Story, Gellar also shared some clips from an interview Prinze did on The Howard Stern Show right before their wedding. During the interview, host Howard Stern asked a young Prinze if he thought his marriage to Gellar would last and bet against the couple's odds.
"So you're going to marry Sarah Michelle Gellar, even though you know that won't last?" asked the radio show host. "Oh, absolutely it will last," Prinze replied. Gellar tagged Stern in the post and jokingly said, "What do you think? I think you owe us."
October 3, 2022: Sarah Michelle Gellar and Freddie Prinze Jr. don't allow their kids to have social media accounts
In an interview for Yahoo! Life's parenting series, So Mini Ways, Gellar shared that she and Prinze are strict parents — at least when it comes to the internet.
"Our rules are probably stricter than most. Our kids don't have social media," she said, referring to Charlotte Grace and Rocky James. "They're allowed to look sometimes when it's our phones."
Gellar added: "I believe kids need to know what their limitations are, and they actually thrive in that environment. We're not mean, we're not unnecessarily strict, but we have rules."
November 16, 2022: Freddie Prinze Jr. says Sarah Michelle Gellar "needs" him to cook
Prinze spoke about his home life with Gellar during an appearance on Australia's The Kyle & Jackie O Show. "I hate a mess. If something is dirty, I clean it," the actor said. "I do the dishes while I'm cooking so there's less s--- to look at."
The Christmas with You star also said he does the laundry and cooks the meals at home. "My mom was a chef and I learned how to cook, and I married someone who couldn't cook," he said. "So I'm necessary. She needs me to live and sustain herself."