The E.T. director is thought to have paid GBP100,000 in 1989 for Russian Schoolroom by U.S. artist Norman Rockwell - unaware it was stolen form a gallery in Missouri in 1973.

The gallery's owner Jack Solomon has filed a lawsuit against Spielberg and the FBI, who he claims let the director keep the painting despite knowing it was stolen.

Solomon is himself being sued by art dealer Judy Goffman Cutler, who sold the painting to Spielberg. She claims she acquired the painting in good faith, and lost Spielberg as a client after Solomon made accusations.

She alleges Solomon lost all claim to the painting when his gallery chain went bankrupt - and is seeking GBP12.5 million for the loss of Spielberg and damage to her reputation."

Spielberg has, meanwhile, defended himself against claims of wrongdoing. His spokesperson Martin Levy says, We are the innocent victim in all this. He bought it in good faith."