An Australian couple bought a "fake" painting for £7500 ($10,000) that is now thought to be by one of Australia’s greatest artists and worth well over $300,000.

Joe and Rosanna Natoli won the painting, which is titled Rejection, with an online bid in 2013 from an English auction house. The work was estimated at £60 to £100, on the basis that it was in the style of UK-born Australian artist Thomas William Roberts (1856-1931), and not by his hand.

The couple was told in Australia that the work was fake. When the Natolis fell on hard times -- losing their savings, home and business -- a friend contacted the BBC show Fake or Fortune? to investigate the work for them.

Experts on the TV program came to the conclusion that the painting was likely a self-portrait by Tom Roberts, painted when he was in London to study at the Royal Academy of Arts in the late 19th century.

The work is now being offered by Philip Bacon Galleries in Brisbane, and the once down-and-out couple thinks it could fetch well over $350,000.