Film star Tom Cruise spent more than two hours signing autographs and greeting fans in London on Monday at the world premiere of his new movie "Lions for Lambs," Hollywood's latest examination of U.S. foreign policy.

"Lions for Lambs," which follows a slew of films related to the war in Iraq and the U.S. military response to the September 11, 2001 attacks, is about two soldiers serving in Afghanistan and political intrigue back in the United States.

Directed by Robert Redford and also starring Meryl Streep, the film has been branded "anti-war" by some media, and its backers are hoping its controversial subject matter will boost it at the box office and going into the awards season.

"I think that films like this are interesting and important and I think it's anyone's place if they want to do it," Cruise told Reuters on the red carpet ahead of the premiere at the London Film Festival.

"We are free to communicate about anything we want and any subject we want, so I think it's absolutely correct."

Asked if he studied any politician in particular for his role as an ambitious senator, 45-year-old Cruise said:

"I studied many. I'll never tell exactly who, but there's many months of research that went into this character to not make him into a caricature but into a human being with real problems and to reflect that idea."

Streep, who plays a journalist in "Lions for Lambs," was not at the premiere, while Redford avoided the media glare and slipped into the cinema via the back entrance.

The film is due to open in U.S. cinemas on November 9.