A Rolf Harris painting owned by a King's Lynn mum goes up for auction tomorrow and could fetch up to �50,000.

Cathy Sims hopes the sale of the portrait of singer Bonnie Tyler, best known for her hit Total Eclipse of the Heart, will help her to fulfil a promise to her five-year-old son and take him to Disneyland Paris this summer.

The artwork has a guideline reserve of �30,000 but was valued at �50,000 by an art expert last year. It will go under the hammer at The Auction Rooms, Lynn Road, Downham Market at 1.30pm.

Miss Sims was given the picture by her father when she was six years old after he bought it for �50 at a charity auction at Sutton Bridge.

She would often sing and dance along to her favourite Bonnie Tyler songs in her playroom which housed the portrait not knowing the artwork's subject was of her favourite childhood singer.

And it was only after her father died in 2005 that the mother-of-one decided to research the artwork and discovered it was painted by Rolf Harris and the subject was singer Bonnie Tyler.

She then took the picture to the BBC's Antiques Roadshow when it visited Layer Marney stately home, near Colchester, last year and was told the portrait was worth up to �50,000.

After the show was aired last year, Miss Sims, who works for Ellab, in Bawburgh, near Norwich, admitted she couldn't afford to keep it because of how much it would cost to insure.

Auctioneer Barry Hawkins said: 'It could be very busy here and it's going to be very interesting to see how it goes because we haven't sold a Rolf Harris painting before.'

Visit www.barryhawkins.co.uk for a closer look a the painting.