Robert Downey Jr will portray Sherlock Holmes as a "bad-ass" in a new Guy Ritchie drama about the detective, the actor has claimed.

RocknRolla helmer Ritchie was contracted by Warner Bros Studios in June to helm a film based on an as-yet-unpublished graphic novel take on Sir Arthur Conan Doyle's most famous creation.

And Iron Man actor Downey Jr - who can next be seen in action comedy Tropic Thunder - has promised that Ritchie has a high-octane approach planned for the character.

"I've got to spend some time with Guy and I love his take on it," he told the Sun newspaper.

"We're both martial arts enthusiasts and in the original stories of Sherlock Holmes, he's kind of a bad-ass and a bare-knuckle boxer and studies the rare, fictional martial art of baritsu.

"If you look baritsu up, they can't even really tell you what it is, so it gives us a lot of leeway."

The announcement of Downey Jr's casting in July followed the news that Sacha Baron Cohen has signed up to play Holmes in a new spoof film, with Will Ferrell to play Dr Watson.

However, Downey Jr believes that the detective is still appealing to 21st century audiences, and Conan Doyle's work offers enough material for both films.

"It's a period piece where you don't modernise it, you just realise how modern it was," he explained.

01/09/2008 15:57:41