Justin Bieber pulled out of a planned 'Tonight Show' skit at the last minute.

The 'What Do You Mean?' singer appeared on Jimmy Fallon's show earlier this month and although it appeared to go off without a hitch, Jimmy admitted that Justin opted out of a sketch they had spent weeks preparing at the last minute.

Speaking to Billboard, he said: ''I wish they'd told me weeks ago because today's the day, and now we have to crunch and think of an idea to do. And I have to say sorry to the crew guys who built the set and the wardrobe people and everyone.''

The cancellation was even more disappointing for Jimmy as just hours before the show he tweeted that Justin would ''do something fun'' before his performance.

However, Jimmy didn't hold a grudge, saying: ''But it's not what he does. He's here to sing, so as long as he's comfortable and it sounds good then we did our job. And if I talk to him and make him funny and make him look good, that's my job. That's all I have to do.''

Meanwhile, Jimmy also revealed he needs more surgery on his injured hand.

host came close to having his finger amputated in June following a freak accident at the home he shares with wife Nancy Juvonen and their daughters Winnie, two, and nine-month-old Frannie, and he still hasn't made a full recovery.

He admitted: ''It's a bummer, but you can't get depressed.''