Ricky Gervais ''knew'' he'd be upstaged by the Muppets.

The 52-year-old comedian hits the big screen in the 'Muppets Most Wanted', alongside children's favourite Kermit, and insists he wasn't worried about his dance scenes when he realised the friendly frog would be sharing the camera with him.

Talking about being upstaged, he said: ''I knew it was going to happen. I knew from day one ... It's funny because the first thing that worried me in the script is the song and dance number. I'm OK at singing, I'm a failed pop star.

''I always sneak in a song, I wrote songs for ['Office' alter ego] David Brent, still doing it, wrote a song for David Bowie for 'Extras', wrote a song for 'Sesame Street' with Elmo. Dancing, a little bit awkward.

''And then I think, 'It's alright, there's going to be a frog on screen dancing. They're not going to care what you're doing with your clumsy little short legs.' So I got away with it.''

Gervais was thrilled to work with the famous puppets and couldn't believe his ''luck'' when he was filming scenes.

He added: ''I love being upstaged by these things. I ruined a lot of takes by just by laughing. Once I went, 'Hah, I'm in the Muppets.' ... 'Cut! Yes you are in the muppets, let's do that again, don't say that though'. I can't believe my luck, I'm a big kid.''