Robert Downey Jr. Talks 'Sherlock' Fight Scenes & The Comment That Got Him Fit

Access Hollywood
Robert Downey Jr. arrives at the The 25th American Cinematheque Award Honoring Robert Downey Jr. at The Beverly Hilton hotel in Beverly Hills, Calif. on October 14, 2011 -- WireImage

Robert Downey Jr. may be a fighting machine as "Iron Man," but he gets into it as a sleuth in "Sherlock Holmes: A Game of Shadows."

"On the first 'Sherlock,' we kind of introduced a little bit of a new take on Sherlock's fighting style and it's been fun to bring that to the next level," he told Access Hollywood over the weekend, of the martial arts employed in the film, due in theaters on December 16.

PLAY IT NOW: Robert Downey Jr. Talks ‘Sherlock Holmes: A Game Of Shadows’

"Also, Guy's (Ritchie) directing style. I think what's not boring about it to me is that there's new camera techniques and there's a lot of thought behind it," he added. "It's not just a bunch of fight moves, you know."

The actor stays in shape for roles like Sherlock and Iron Man, and he confirmed that after "Tropic Thunder," his wife - "Sherlock" producer Susan Downey -- helped inspire him to get fit.

VIEW THE PHOTOS: Hollywood’s Man Of ‘Iron’ — Robert Downey Jr.

"She told me I had turned into a bit of a slob," he revealed. "I blame it on Bubba's Burgers. Probably one of the great burger establishments known to mankind."

While a weight comment can be tough for some to hear, Robert thought it over and decided he agreed with Susan.

"As usual, I looked at her like, 'All right, she's got some warped perception of what's going on here,' and then when I realized that I couldn't fit into any of my clothes, I honestly thought maybe because I'd been in a different climate -- that they'd all shrunk, and then eventually I came around."

VIEW THE PHOTOS: Hollywood’s Smokin’ Hot Couples

Copyright 2011 by NBC Universal, Inc. All rights reserved.
This material may not be published, broadcast, rewritten or redistributed.