Ian McShane told reporters that he will play a good guy for a change in the upcoming Renee Zellweger thriller movie Case 39.

"That's a sort of a Bad Seed scenario," McShane said in a conference call with reporters on Wednesday while promoting his upcoming NBC series Kings. "You have Renee Zellweger and this extraordinary kid who plays the kid that you think it's the parents that are evil, but of course it's not."

The long-completed movie, which is likely to be released later this year, follows a social worker (Zellweger) trying to a help a young girl (Jodelle Ferland) whose parents appear to be abusing her. The truth of the situation, however, is far more terrifying than the social worker ever dared imagine.

McShane, who is perhaps best known as profane saloon owner Al Swearengen on HBO's Deadwood, plays a virtuous law enforcement officer this time around.

"I play the good cop," McShane said. "I play a good guy, a good, regular cop who meets ... I shouldn't say that. I won't give that away. No. But it's a Bad Seed child, is Case 39." The American/Canadian production was directed by Christian Alvart.