Gary Barlow and Andrew Lloyd Webber will join forces to write a song for the Queen's diamond jubilee in a collaboration to be captured in an hour-long documentary on BBC1.

The tune will be performed at the star-studded diamond jubilee concert outside Buckingham Palace on 4 June, which will feature artists including Sir Paul McCartney, JLS and Sir Elton John.

More than 1 million people have applied for tickets for the concert, according to the BBC. The majority will have to watch it on BBC1 as the venue has capacity for just 20,000 people.

The documentary is a minor coup for the corporation, with Barlow best known (outside of Take That) as a judge on ITV1's The X Factor, while Lloyd Webber recently announced that his latest West End talent search, for a revival of Jesus Christ Superstar, will be switching from BBC1 to ITV1.

To write the song Barlow (but not Lloyd Webber) will travel the world to discover what the Queen means to the people of the Commonwealth.

Barlow said: "This is probably the biggest challenge I've ever taken on musically, I'm so excited and thrilled to be a part of it."

Barlow and Lloyd Webber announced the venture on Chris Evans's BBC Radio 2 breakfast show on Friday. The documentary was commissioned by BBC1 controller Danny Cohen.

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