Actress AnnaLynne McCord and actor Dominic Purcell arrive at the Drawing Hope Int'l Masquerade Gala at The Mark on March 18, 2012 in Los Angeles, California. Credit: Todd Williamson/

It was fun while it lasted.

Fifteen months after Dominic Purcell, 42, was first spotted kissing AnnaLynne McCord, 25, on the set of 90210 in L.A., the couple has called it quits, multiple sources tell Us Weekly. The stars met while shooting Officer Down in early 2011; the film has yet to be released.

One insider believes McCord decided to end the relationship after her two sisters, Angel and Rachel, both got engaged. "Though AnnaLynne's not in a rush to get married, her sisters getting engaged must have made her evaluate her own relationship to some degree," the insider tells Us.

Adding that Purcell seemed "more into AnnaLynne than she was into him," the insider says the starlet "recognized the imbalance in their romantic dynamic."

A second source tells Us McCord "fell for Dom hard" in the beginning. Despite their 17-year age difference, "they made it work."

Prior to his relationship with McCord, Prison Break star Purcell was married to Rebecca Williamson; they split in 2007. The former spouses are parents to son Joseph, 13, daughter Audrey, 11, and twins Lily-Rose and Augustus, 9. McCord dated hunky Twilight star Kellan Lutz, 27, on-and-off from 2008 to 2011.