Katherine Heigl's husband was convinced to commit to her by John Mayer.

Katherine Heigl

Katherine Heigl

The '27 Dresses' star was hanging out with the 'Free Fallin' hitmaker around the time she went on her first date with her now-husband Josh Kelley and he decided to make their relationship official as he believed she had a crush on the singer.

Recalling what happened, she said: "John and I grew up in neighbouring towns and we knew some of the same people and some friends in common. We met up at one of his concerts. Just friends! Just friends! But Josh and I were probably dating about a month, and it was unclear where the relationship was going; I like clarity. I didn't know if he was as serious about me as I was about him.

"I had run into John, who was in town making a record or something. We were just hanging out, having drinks, having dinners - as friends! Totally just friends! He wasn't interested in me that way. He would talk to me about other hot girls and stuff; it was friends."

And host James Corden quipped back that "it was getting to the point now you're saying 'friends' so much I'm starting to think you slept with him," making Katherine laugh as she admitted he wasn't the only one who thought so.

Speaking on The Late Show with James Corden, she added: "Josh to this day doesn't quite believe me. Anyway, that's a whole another argument for another time. But yes, I did use it a little bit to put a fire under Josh. It was like, 'Hey, if this isn't exclusive and you're going to be seeing other people, then I'm going to keep seeing John."