Credit: Victor Spinelli/

Chuck star Zachary Levi is back on the market. The actor, 29, has broken up with singer Caitlin Crosby after two years together, a source tells exclusively.

"He broke up with her on Saturday before his big NBC premiere aired," the pal explains, adding that the couple had recently returned from a "great vacation" in Turks and Caicos and Puerto Rico.

Levi's reason? "He told her it was bad timing and if God brings them together in the future it's meant to be," the pal sniffs, adding that "this isn't the first time" the actor has tried to end things with Crosby.

"Guess he thinks he's too big a 'star' now," says the source. "No more Mr. Nice Guy."

Crosby, 26, changed her Facebook status to "single" on Tuesday afternoon. Also on the social networking site: a foreshadowing photo of the couple on their island vacation. "In the photo, he's drinking beer, and she's reading The Shack," the friend observed.

"She is heartbroken, but she is already writing great songs about it," the pal says. The singer will keep herself busy with an upcoming tour to promote her album Flawz, the friend notes. When reached for comment, a rep for Crosby told, "We don't comment on our clients' personal lives."