Bradley Cooper talks about 4-month marriage to Jennifer Esposito

(CBS) Bradley Cooper has been photographed all over the world with girlfriend Renee Zellweger, but few people may remember that "The Hangover" star was already married - very briefly - once before.

Cooper explained his four-month marriage to actress Jennifer Esposito on Howard Stern's radio show on Monday.

Pictures: Stars' first spouses

The actor, now 36, married Esposito (who currently stars on the TV series "Blue Bloods") in December 2006. She filed for divorce in May 2007.

"It was just something that happened," Cooper said, without detailing exactly when he knew things were finished. "The good thing is, we both realized it...Sometimes you just realize it."

When Stern pressed him to tell more, the actor added, "It just wasn't right. It's interesting...things happen!"

Cooper added that it's "not true" that the experience turned him off to marriage for good.

"Making any declarative statement [like that] is a joke," he said.

Zellweger also has a short marriage under her belt - in 2005, she married country singer Kenny Chesney. Their union was annulled four months later.