Eminem's forthcoming album, 'Relapse', could feature a guest appearance from Sir Elton John, it's been reported.

Sir Elton reportedly spent half a week in the same recording studio in Detroit where Eminem was recording the album last October.

The pair, who performed together at the Grammy Awards in 2001, have spoken in the past about their desire to collaborate on record.

A witness told The Independent: "No one realised the significance, though the Detroit Free Press did mention that Elton had been in town”.

The witness, who wasn't named in the article, said the two musicians had a mutual respect for each other.

“Elton really gets his music. Anything they produce will be total dope: some of Em's biggest records have been collaborations with mainstream pop stars – Dido on 'Stan', for example – and they really don't come much bigger, or more mainstream, than the man with the red piano."

'Relapse', which is due out this Spring, is already known to feature guest appearances from 50 Cent and the album's producer Dr Dre.

Two tracks from the record – 'Relapse' and 'Crack A Bottle' – have already leaked online.

The album will be the follow-up to Eminem's 2004 release 'Encore'.

(by Jason Gregory)