Katy Perry and Robbie Williams aid Japan victims

Katy Perry and Robbie Williams are taking part in an online auction for victims of the Japanese earthquake.

The pair are joining a host of artists in donating personal items to the Japanese Red Cross over the next three weeks.

Robbie is auctioning off a lifesize cardboard cut-out of himself on eBay and Katy Perry is selling off a signed poster.

Other artists involved in the relief effort include Tinie Tempah and David Guetta.

Their record label, EMI, will match all funds raised from the auction.