Washington, Feb 28 : American actor Robert Downey Jr. has given credit to Coldplay frontman Chris Martin for his recent weight loss in the upcoming movie Sherlock Holmes.

Downey Jr., 43, is currently filming scenes as the fictional detective in a new big-screen adaptation by director Guy Ritchie, and he has had to slim down considerably for the role.

The Iron Man star says that every time he is tempted to have a snack, he remembers Martin's advice.

"He's a huge Sherlock Holmes fan. He said to me before we began `You've got to be gaunt. You''ve got to be as skinny as you possibly can to play Holmes,'" Contactmusic quoted him as saying.

"So every time I''m reaching for a muffin I just think about Chris Martin and skip the snack. That''s been tough," he added. (ANI)