In the romantic image, the couple, who met in 1997 on the set of the horror flick I Know What You Did Last Summer and began dating in 2000, are smiling as they dance in their wedding attire. "13 years #happyanniversary," the Crazy Ones actress wrote.
Gellar, who shares Charlotte Grace, 5, and Rocky James, 2, with Prinze Jr., continued with a quote by poet Roy Croft. "I love you not only for what you are, but for what I am when I am with you. I love you not only for what you have made of yourself, but for what you are making of me," she shared.
The celeb couple married in Mexico in 2002; director and choreographer for Gellar's Buffy the Vampire series, Adam Shankman, officiated the nuptials. Since then, the pair have worked together on many family-oriented projects, including Scooby-Doo, Scooby-Doo 2: Monsters Unleashed, and animated film Happily N'Ever After.
What do you think of Sarah Michelle's sweet anniversary message to Freddie? Tweet with @UsWeekly using the hashtag #stylebyUs!
Get celeb fashion, beauty tips, and more delivered directly to your inbox. Sign up for the Us Weekly Style & Beauty newsletter now!