(Cover) - EN Showbiz - George Michael may have to pull out of a charity performance alongside Alicia Keys as his cheek looks like a "hairy football".

The British singer is due to take to the stage at the Keep a Child Alive Black Ball charity event in London on Wednesday. He was delighted to be asked to sing at the event, which is being hosted by Alicia Keys who founded the charity - and Mark Ronson and was looking forward to it. However, George fell ill over the weekend and is now unsure if he'll be fighting fit in time for the ball.

"On the weekend, got some kind of infection in my lower jaw and the left side of my face now resembles a hairy football. I look like Marlon Brando ( I wish....) in the Godfather if they forgot to stuff the right cheek!" he wrote on Twitter.

"Anyway the point is I dont know if it will clear up in time for Wednesdays Black Ball Charity event with Alicia Keys... Which would be terrible, I don't want to let down the charity, which is excellent, and I would love to sing with Alicia, shes wonderful.... (sic)."

Further details of George's condition are unavailable, although he has promised to give fans regular updates.

The ball is held annually to raise money to help families living with HIV and AIDS in Africa and India.

Alicia was thrilled when George was added to the bill, releasing a statement praising the singer's talents.

"I've been a fan of George Michael for as long I can remember. He is a legend and an inspiration I'm honoured that George has lent his voice to our KCA cause and I'm so excited that he's singing for us at the Black Ball in London. It is going to be an amazing night!" she said. (C) Cover Media