'Lost' actor Matthew Fox - who plays a WWII Army Officer in Peter Webber's new movie 'Emperor' - says the cast were walking on egg shells around Tommy Lee Jones during filming. The historical-drama follows Fox's character General Bonner Feller who is tasked with deciding whether Japan's Emperor Hirohito should be hanged as a war criminal.

Speaking to the Hollywood Reporter, Fox - who appears in nearly every scene of the movie - explained how he had been shooting for around eight weeks before Jones turned up to shoot his scenes. "The combination of Tommy's persona, and what he's done as an actor, combined with the fact that he's playing MacArthur, one of our most iconic U.S. military figures, you could feel the energy on the set; people were on eggshells," he said.

Jones has always been infamous for his straight talking rough around the edges persona - something controversial Oscars host Seth MacFarlane played on last month. For Fox, it only added to the role. "I knew it was going to work for us because I think that's probably the way that all the people who worked around MacArthur in 1945 felt," he said.

Though Jones was a towering presence throughout the shoot, 'Emperor' is very much Fox's movie. Despite personal problems over the past year, the actor is establishing himself as one of the most sought after names in Hollywood. He stars opposite Brad Pitt in World War Z - a movie likely to be the biggest of 2013. Talking about leading his latest flick, the actor explained, "I haven't done that. Even with the television experiences I've had, I've always been involved in a big ensemble cast and had my moments when somebody else was heading the charge. It was a bit daunting.It was hard work but worth it."

'Emperor' hits theaters in the U.S. on March 8, 2013.

Watch the 'Emperor' trailer: