Former Playboy playmate Anna Nicole Smith is being sued by a film producer for $4 million. Producer Vince Offer says the multi-millionairess agreed to film Underground Comedy Movie, The (1999) but backed out in 1996, saying it would be detrimental to her career. Smith has been involved in a tug-of-war over the estate of her late billionaire husband J. Howard Marshall A judge last month awarded her $449.7 million, ruling she had been wrongly deprived of her share. She is still involved in a probate court battle over the estate's value. Smith was unavailable for comment about the film which was released in 1999 and featured Joey Buttafuoco and Gena Lee Nolin.