Match made in heaven?

And you thought Eminem's chainsaw was scary...

By BBC News Online's Denise Winterman

Just when you thought the only way left for Sir Elton John to shock you was to cut up his credit cards, he reveals his biggest surprise yet.

When it comes to duets, he is best known for his sing-songs with the likes of Kiki Dee, not with controversial rappers such as Eminem.

But the pair will sing together at the Grammys in Los Angeles on 21 February.

Eminem is a genius. Listening to his album I thought a nuclear bomb had gone off

Sir Elton John

The openly gay Sir Elton is acknowledged as a champion of homosexual causes.

He is cited as a major influence by stars including George Michael, Ronan Keating and Robbie Williams, adding to his reputation as a godfather of commercial pop, the king of the middle of the road.

Eminem, by contrast, has been branded homophobic because of the anti-gay content of his songs.

He has also openly attacked the songs pumped out by more mainstream artists, with Britney Spears and Christina Aguilera among his targets.

Hardly a match made in heaven then, but it seems the two have a mutual admiration for each other that people are finding hard to understand.

Sir Elton said of the rapper: "Eminem is a genius. Listening to his album I thought a nuclear bomb had gone off."

'Clever'

He claims to find Eminem's lyrics inoffensive and his music clever.

The rapper has also expressed admiration for Sir Elton, although he is reported to have said that he only recently realised the singer was gay.

Despite their obvious differences, these two might have more in common than people think and it is possible they see a bit of themselves in each other.

Creating an artistic alter ego is just one things in which they both excel.

Eminem has been called a genius by Sir Elton

Eminem's fictional alter ego, Slim Shady, must have psychologists in a frenzy of excitement.

The rapper may come from a poor white background but on stage he becomes a tough street poet mixing with gangs, taking drugs and saying all the rude things his mother wouldn't allow.

Inventing a stage persona is nothing new for Sir Elton.

Though he has toned things down over the years, in the 70s he transformed himself into anything from Donald Duck to Wolfgang Amadeus Mozart on stage.

Even on a bad day the satin hotpants he sometimes modelled made Eminem's current stage attire of a hockey mask and chainsaw look lightweight.

Excesses

Behind the scenes both have also seen life imitate art, with the excess of their alter egos creeping into real life.

According to Byron Williams, a former bodyguard who has written an insider's account of Eminem's rise to fame, his drug taking was excessive.

"He took so many drugs, popping ecstasy at breakfast and weed (cannabis) at lunchtime, that he often did not know what country he was in," he is quoted as saying in a Sunday Times interview.

By his own admission, Sir Elton has spent a lot of time in a similar state.

Ultimately some people might think Eminem is having a laugh at Sir Elton's expense.

The rapper has been condemned for his lyrics

But it seems that he is not the only young "alternative" artist wanting to work with the superstar.

Moby, the ambient whiz, has said Sir Elton is one of the greatest vocalists alive.

Perhaps more surprisingly, leading American producer Ross Robinson, guru of the Nu Metal movement and the man behind hardcore rockers Limp Bizkit, also has admiration for Sir Elton.

"When he was young and his voice was on fire, he was so hot," he said in an interview in the Daily Telegraph.

Maybe Eminem is setting the pace in music once again or Sir Elton is tired of the quiet life.

Whatever, it will probably ensure one of the Grammys' biggest television audiences.

And to think the music world was rocked when Run DMC and Aerosmith got together.