Kristen Bell is engaged to marry longtime beau — and When In Rome co-star — Dax Shepard, a rep for the former Veronica Mars star confirmed to UsMagazine.com on Sunday.

Shepard, 35, proposed to the 29-year-old beauty over the holidays, according to Us, who notes that Kristen debuted her impressive sparkler at tonight’s 52nd annual Grammy Awards.The couple started dating in January 2008. In a recent interview with Women’s Health, Bell described the couple’s relationship on set as competitive.

“We were trying to one-up each other,” she laughed. “That’s what we do at home, too. It’s like, ‘Wait – watch me do this funny bit.’ ‘No, watch me do this funny bit!.”