The American Horror Story star, 47, shared a loving tribute in honor of Taylor on Instagram Friday.
"Love of my life. The one. The only one," she wrote in the caption alongside a photo of Taylor. "January 14th is my favorite day of the year- a day to unabashedly celebrate you @hollandvtaylor I am the luckiest of the lucky. I love you only."
"Happy Birthday magical poet darling. 💕," Paulson added.
She also posted a photo of The Chair star on the beach on her Instagram Story, writing, "Birthday beach babe."
Paulson and Taylor, who have been dating for nearly six years, have kept a relatively low profile throughout their relationship. The couple was recently spotted out with friend Diane Keaton in Los Angeles in November, but before that had not been photographed in public since an August 2020 shopping trip.
That month, Taylor spoke exclusively with PEOPLE and revealed that the COVID-19 pandemic allowed the two to get to know each other better.
"Of course, Sarah and I didn't need to be brought closer together," she added at the time. "We have a very tight, close relationship within each other's thoughts. We share everything that's going on."
Paulson previously said during a 2019 appearance on Watch What Happens Live with Andy Cohen that she and Taylor first began their romance on Twitter.
"It's a long story. We met a very, very long time ago. I was with someone else and she was too," she said. "We were doing a thing at [actress] Martha Plimpton's house. It was for an organization that she was working with and we were both doing a little PSA for it."
"We sort of breezed by each other and then started following each other on Twitter … and then …" Paulson continued, revealing that Taylor slid into her DMs.
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In a previous interview with Elle, Paulson also spoke about how she hopes her public love with Taylor could leave a lasting impact on anyone who may need it.
"I didn't choose to fall in love with the person I fell in love with," she said in 2018. "But I think why it's interesting to people is that on paper, it's unconventional."
Paulson added at the time, "For a person who might find themselves in a situation that they fear will be misperceived or judged, maybe they could see me living my life in a way that is authentic to me— just trying to be as real as possible. If that inspires anybody else, that can't be a bad thing."