George Clooney's new film about the real-life art experts who retrieved paintings and sculptures from the Nazis during World War Two has been given a boost thanks to the discovery of a lost treasure.

Johann Conrad Seekatz's painting Saint Philip Baptising a Servant of Queen Kandaki was taken from the National Museum in Warsaw, Poland during the German invasion, and was considered lost, perhaps destroyed, for almost 70 years.

It was spotted in an art gallery in London last year (13), and following an investigation, the painting has been handed back to Polish officials.

The news of the handover comes as Clooney's new film The Monuments Men hits cinemas in America.

In the movie, the actor/director plays the leader of a small band of professors and art lovers who tracked down valuable paintings and other pieces claimed by Adolf Hitler's army as it marched through Europe in the 1940s.