Robbie Williams and George Michael are among a number of pop stars who have personalised copies of John Lennon's re-issued single Imagine to raise money for charity.

The two chart-toppers have been joined by the likes of Bono, the Pet Shop Boys and Tina Turner to add their personal style of artwork to a sleeve of the single.

The customised records are being auctioned on the MSN UK website with each eventually being sold to highest bidders before 4 January. The money raised will go towards helping the homelessness charity Shelter.

Lennon's widow Yoko Ono is behind the idea. She asked music stars if they would help to raise funds for Shelter by creating the one-off works of art while she too worked on one.

She said: "It's great to be involved in a UK charity that draws attention to such a worthwhile cause."

The pictures, painted or drawn, are all very varied. Williams added a cheeky Cherub to the black and white picture of Lennon at his piano.

The Pet Shop Boys individualised their sleeve by adding a speech bubble coming from Lennon's mouth.

It says: "Cliff is over if you want it" - a reference to Sir Cliff Richard's single The Millennium Prayer being knocked off the Christmas number one slot by Westlife's double A-side single.

U2's Bono chose to add a riot of colour to the black and white cover, complete with Christmas tree, and signed it B Ono.

Chris Holmes of Shelter said:"This is a great opportunity to raise awareness about homelessness and, thanks to Yoko Ono, will also raise vital funds so that we can continue our work."

Other contributors to the money raising scheme include Tina Turner, Ronan Keating, Brian May from Queen and Neil Hannon of Divine Comedy.