One would think that after being axed from the US series of The X Factor after one season, Nicole Scherzinger would be on her best behaviour when she was invited back to be a guest judge on the UK version.

But the singer was late to the auditions at London's O2 Arena today - holding up filming by an hour.

Nicole kept her fellow judges and the audience waiting while she finished getting ready.
Diva behaviour: Nicole Scherzinger held up filming and had her fellow judges waiting today when she was an hour later for X Factor auditions in London
Nicole is filling the spare judging spot following Geri Halliwell, Leona Lewis and Rita Ora.
The former Pussycat Dolls singer flew to London from the Riviera, where she was enjoying a post-Grand Prix holiday with her F1 driver beau Lewis Hamilton.But she was back in work mode yesterday, tweeting: 'Looking forward to seeing my UK fans in London at the 02 on Wednesday!!! I'm so grateful and blessed to have them!!! #secondhome.'
On to the next: Nicole is the third guest judge so far this series, following Geri Halliwell and Rita Ora
While Tulisa came out as the standout judge on last year's panel, the singer was heckles by the audience today when she said she didn't know a song a contestant chose - which turned out to be by her 'friend' Jessie J.

Jessie was by Tulisa's side helping her select contestants during last year's judges houses rounds, so it was surprising when she said she hadn't hear of the track.

When it was pointed out that it was her friend's song, 
All is forgiven: Gary Barlow didn't seem to mind once the auditions got under way
Today saw the return of singer Joe Cox, who made it right through to the judge's houses round last year, before being axed by Gary.

Joe wowed the crowd with Katy Perry's The One That Got Away.

Insisting that he has no hard feelings towards Barlow, Joe told the Take That star: 'I want to say thank you for saying no, because I wasn't ready.'
Not a fan? Tulisa was heckled when she failed to recognise a song by her 'friend' Jessie J
Tulisa and Louis both told Gary that had Joe been in their category, they would have put him through to the live shows.

Louis- 'You've convinced me we've found someone brilliant,' said Louis. 'I predict you are one of the people to watch in this competition because you are bigger and better.'

Gary revealed: 'Your "no" was the hardest for me by far and I've been waiting for this moment. You are going to be a great artist Joe, welcome back.'