Bidders could come away with a painting they love as well as the bonus of it being by a famous artist in an unusual auction to support sick children being cared for at Royal Brompton Hospital .

Celebrated artists including Sir Antony Gormley, Norman Ackroyd and Gavin Turk have all contributed postcard-sized original works to the Secret Rose Auction, which will begin at midday on Thursday (May 26) and run until 8.30pm on June 9.

But those bidding will not know if the the art work they purchase was created by a leading light of the British art movement or an amateur until after the event is finished.

Proceeds from the event will be used to refurbish a playroom for children with heart and lung conditions who are in-patients on the paediatric Rose Ward at the Chelsea hospital.

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Among those who have contributed to the auction is John Keane, the celebrated British artist whose paintings have contemporary political and social themes.

He said: “I’ve painted a postcard for the Secret Rose online auction for the paediatric Rose Ward at Royal Brompton Hospital.

"I hope it will raise money to help refurbish the playroom for children with heart and lung disease.”

All the postcards will be on display from May 30 to June 8 at the Royal Brompton Hospital in Sydney Street, and Harefield Hospital in Hillingdon , culminating in a final one-day exhibition at the Flowers Gallery in Shoreditch on June 9 from 10am to 6pm.

The artists behind the paintings will remain anonymous until the auction has ended, encouraging potential buyers to bid big for pieces they like with the bonus that they might purchase a celebrity ‘miniature’.

To art can be viewed here , and bids can be made here .