(Cover) - EN Showbiz - George Michael is "nervous" about performing at the Olympic Games Closing Ceremony this week.

The British singer is appearing at the prestigious event on Sunday, which will mark his return to the stage after a series of health problems which put a halt to his tour last year.

George - who was hospitalised for pneumonia - took to his Twitter page to share his concerns with his followers.

"Hey everyone, how are you. Spending most of the next week rehearsing like crazy for the Olympic closing ceremony.....," he wrote, before adding: "Obviously a bit nervous not having played for nearly a year, but rehearsals sounding great so far!"

George's post about his Olympics performance comes after he announced he will be playing "a couple of songs" at the event in July.

The 49-year-old star confirmed the news on TV so was amused when one fan asked whether his turn on the stage was supposed to be a "big secret!".

"Oh, and , secret? It's been all over the press for weeks, and I think you alll needed to be put out of your misery! (sic)," he exclaimed.

Also rumoured to be performing alongside George are the Spice Girls, however, their part in the Olympics Closing Ceremony has not yet been confirmed. (C) Cover Media