Pop legend SIR Elton John joined Prince onstage in London on Thursday (13Sep07) to perform a duet of THE Beatles' hit, LONG AND WINDING ROAD. John appeared when Prince returned for an encore, during one of his 21 concerts at the capital's O2 Arena. Prince played guitar while the Rocket Man sang and played piano. The pair embraced afterwards, and Prince told the crowd, "You know who it is - Sir Elton John!" Prince's performance at the venue turned into a mammoth event. He worked his way through two long encores - before decamping to neighbouring venue Indigo and kicking off an aftershow performance that lasted more than two hours. The late night set including a cover version of Led Zeppelin's Whole Lotta Love, a tribute to the rock band who announced a reunion concert on Wednesday (12Sep07).