Geri Halliwell and George Michael have reportedly fallen out over his failure to write the Spice Girls' comeback single. 
The 'Faith' singer had agreed to pen a track for the reunited girl band, which would have been released in time to battle for the Christmas number one spot.
However, Geri - who is a long-time pal of George - was said to have grown frustrated with how long he was taking and instead teamed up fellow Spice Girl Emma Bunton to write 'Headlines (Friendship Never Ends)', much to George's anger.
A source told Britain's The Sun newspaper: "George was more than happy to write a song. But Geri was frustrated how long he was taking to finish it.
"She wrote 'Headlines (Friendship Never Ends)' with Emma instead and George was furious. He has been fed up with Geri's 'me, me, me' attitude.
"She is still really good pals with his boyfriend Kenny Goss who's been acting as a go-between in their battle."
The band - Geri, Victoria Beckham, Mel C, Emma Bunton and Mel B - have decided against releasing the single in time for the Christmas number one spot with the song going on sale next Monday (20.11.07).
Geri - who quit the band in 1998 - recently insisted there are no arguments among the band and they are all finding it easy to be singing together again.
She said: "We're working hard and it's like we've never been apart. I really like it when we're singing in harmony with the band. It's funny that 10 years on each of us still remembers our harmony lines. It's like riding a bike - you just don't forget. It's like it's ingrained in us."