However, Philip Mould OBE from Antiques Roadshow, having seen a photograph of the painting, dismissed it as unlikely to be the legendary pop artist’s work.

Adding to the doubt, the piece it is signed ‘Andy Warhol’ and only changed his name from Andrew Warhola in 1949.

However Fields, 48, said he bought the work of art from a drug user whose aunt used to look after Warhol when he was a child.

The artwork- from the Thirties – is believed to have been drawn by the artist when he was 10 or 11.

Field says he has had it valued at £1.3million – but it could fetch ten times as much if sold.

Weirdly, he has vowed to hang on to the piece which features Rudy Vallee, an actor and singer in the 1930s.

Fields, who bought it in 2010, said: ‘I bought some sketches by Gertrude Stein at the garage sale and the Warhol work was actually behind one of these.