James Corden: I could explode with happiness

James Corden thought his "head was going to explode" while shooting Begin Again because his life was so good.

The British star plays a struggling musician called Steve in the release, which also stars Keira Knightley and Adam Levine.

While he was shooting the picture, James was also appearing in Broadway play One Man, Two Guvnors, and at times he had to pinch himself about how far he'd come.

"John [Carney, director] encouraged us to have fun. And there was one day where I did the play in the day and Gene Wilder came to see it and said some really nice things, then I went to shoot this scene in the film where we're all on the roof of a skyscraper in New York. It was so amazing - I thought my head was going to explode!" he laughed to British magazine Heat.

Steve plays the guitar and kazoo, and he helps Keira's character Greta when she decides to record an album. James had to work hard to ensure he was believable in the scenes that called on him to strum a tune and he's proud that he looks convincing - even if he doesn't know as much as it seems.

"I learned to play about five chords on the guitar and knew enough to patch something together that would make me look like I knew what I was doing," he said. "I'm really proud of the whole film. I think it's a lovely movie to come out right now, in the middle of all the summer blockbusters - it's a little bit nicer to see something about people finding their way in life."

The star added that Begin Again is exactly the kind of flick he heads to the cinema to see, and he would opt to watch one like it every time over a major movie.