James Corden has admitted his new role as host of The Late Late Show could be a "disaster".
The Gavin And Stacey star was announced as the surprise replacement for Craig Ferguson on the CBS talk show in September, despite not being massively well known in the US.
Due to start on the show in March, he told Deadline: "I think I'll be better at acting than hosting a TV show - it's going to be awful. Every bit of this is a massive risk. It's brave to take a guy you never heard of and give him an hour of TV."
He continued of prepping for it: "We have a staff of two. No one is employed. We're so far away [from prepping]. I have another series to shoot at home yet. I've got to promote Into The Woods, and there's a film I have to finish writing.
"Literally, the employees on The Late Late Show are myself and my best friend Ben (Winston). There's a lot to do between now and March. Rehearsing? Jesus, we might not have time to rehearse.
"The whole thing is going to be a f***ing disaster. Remember this phone call! You'll say, 'To his credit, he called it early on.' There's no reason for this show to work."
James, who stars in upcoming musical fairytale Into The Woods alongside Emily Blunt and Meryl Streep, said he wanted the chat show to be "a party every night. I'll be the youngest of the guys in the chairs in late night. By definition, we have to make it the youngest and freshest show."
Asked why he'd agreed to host, he replied: "Why not? There are any number of reasons. I never wanted a career to be just one thing. Like at home, I hope I can still go back and act. It's my dream to do a musical on Broadway, to do another play, to try and write a film that gets made and to write another TV series.
"The challenge of [late night show hosting] is so much harder than being an actor in films. I know a lot of people think being in films is amazing. It's not. You spend a lot of your day in a caravan, in a car park. So, the thrill and the challenge of trying to make an hour of television is far greater than playing someone in some biopic."