Sir Elton John documentary to open Tribeca festival

Sir Elton first played with Leon Russell (l) in the early 1970s

A screening of a documentary about Sir Elton John will open this year's Tribeca film festival, to be followed by a live performance by the singer.

Cameron Crowe's film The Union follows Sir Elton and his musical hero, US songwriter Leon Russell, as they produce a collaborative album.

The outdoor event, in Lower Manhattan, will kick off the event on 20 April.

Other films to be shown at the 10th annual festival, which will run until 1 May, will be announced in coming weeks.

"To have Elton, whose music transcends generations, perform... is an extraordinary gift," said Jane Rosenthal, who co-founded the festival in 2002 with her philanthropist husband, Craig Hatkoff, and actor Robert De Niro.

Sir Elton, 63, and Russell, 68, played together in the early 1970s and composed tracks for The Union with the former's longtime co-writer, Bernie Taupin.

According to Sir Elton, he and Taupin were "obsessed" by Leon's music when they first went to the US in 1970 and regarded him as "some kind of musical god".

Last year's Tribeca film festival opened with the animated sequel Shrek Forever After.