Kate, 37, accompanied the 92-year-old monarch as they opened Bush House, a new education and learning facilities on the Strand Campus.
Rather sweetly, the pair shared a blanket in the car on the way to the event.
The engagement marked a milestone for the duchess: it was the first time we’ve seen the royals out and about together, without another member of the Royal Family present and outside of palace walls.
The Duchess of Cambridge visited Leicester with the Queen and the Duke of Edinburgh in March 2012 and they have also hosted receptions at Buckingham Palace together, including the Dramatic Arts Reception in 2014.
The pair toured the university’s facilities, including the faculty’s new roof terrace and also viewed a robotics demonstration, including robotic surgery.
The Queen looked lovely in a rose pink Stewart Parvin cashmere coat with a matching hat by Rachel Trevor Morgan, paired with a pink sapphire and diamond brooch.
Kate, meanwhile, ensured she didn’t outshine the Queen in a new grey pleated coat dress by Catherine Walker with belt and contrast collar detailing.
She appeared to be wearing the same black Lock & Co hat worn on her visit to Leicester with the Queen in 2012.
Black suede pumps and her Mulberry Bayswater clutch bag finished the outfit.
The duchess had a second engagement on Tuesday afternoon, at the Foundling Museum in London.
She was announced as Patron ahead of her visit, where she learned how the organisation works with art and artists to transform the lives of vulnerable and marginalised young people.
Kate, who remained in the same outfit for her second duty of the day, gave a speech at museum, saying: “I am passionate about improving children’s life chances and giving them opportunities, so that they can look forward to the best possible futures, fulfil their whole potential, and have the freedom to explore their creativity.”