By Mike Collett-White

LONDON (Reuters) - Robert Downey Jr. is to play Victorian super sleuth Sherlock Holmes in an upcoming blockbuster that studio Warner Bros. hopes will become a lucrative new franchise.
The 43-year-old said one reason he was chosen for the role may have been his involvement in action movie "Iron Man," which earned over $570 million in global ticket sales this year, and he promised his Holmes would be the best screen portrayal ever.


"In case you aren't aware I had a hell of a summer, and it's made me much more viable to play a lead role than I might have (been) in the past," Downey Jr. told reporters in London, where shooting on "Sherlock Holmes" is about to begin.

When asked what he could bring to a character portrayed countless times on film and television, he joked: "Clearly I'm going to do it better than it's ever been done.

"The more I read about it the more overwhelmed I was by the weight of it and the amount of people who will be watching to see if it's gotten right."

Director Guy Ritchie said "Sherlock Holmes" was his biggest movie "by a long shot" in terms of budget.

Producer Joel Silver would not name the figure, but he called the budget "healthy" and said plans had not been affected by recent turmoil on the financial markets.

"What we've done is hopefully launched a franchise of Sherlock Holmes stories," he said.

Warner Bros. may be hoping the series can replace Harry Potter, which has three films left to go and could end in 2011. The franchise based on J.K. Rowling's boy wizard tales has grossed $4.5 billion at worldwide box offices so far.

"TRUE TO ORIGINAL"

The new Sherlock Holmes film is based on an original story by Lionel Wigram inspired by the Arthur Conan Doyle books.

"I really knew Sherlock Holmes from tapes -- I wasn't a very good reader," said Ritchie. "What I had imagined in my mind was not exactly what I'd seen previously manifested on film.

"I am a fan of many of the previous productions of Sherlock Holmes. I just think we can have a different take and I'd like to think a better take."

He added: "We're trying to be as authentic as we can to what we see as the original Sherlock Holmes. We are also specifically keen on keeping it authentic to Conan Doyle."

The director said he had never considered involving his wife Madonna in the new movie, and originally thought Downey Jr. may be too old for Holmes.

As well as bringing more action sequences to the story, the dynamic between Holmes and loyal assistant Dr. Watson looks set to differ from what audiences are used to with the casting of heartthrob Jude Law in the part.

Silver was aware that the announcement of Ritchie's Sherlock Holmes project came soon after another film based on the 19th century detective was unveiled starring Sacha Baron Cohen in the lead and Will Ferrell as Watson.

He said the movies would be released at different times -- Sherlock Holmes has a tentative release date of 2010 -- and Ritchie joked: "We've done as much as we can to sabotage Sacha Baron Cohen."

(Editing by Paul Casciato)
© Copyright 2008 Reuters.