Borat and Ali G star Sacha Baron Cohen has signed up to play Sherlock Holmes in a new Hollywood film about the fictional detective.

US actor Will Ferrell has been cast as Watson, the sleuth's crime-solving partner in the big-budget movie.

Holmes has been absent from the screen since Rupert Everett revived him on TV as an opium-smoking detective four years ago.

But Baron Cohen's turn as Holmes could end up competing with director Guy Ritchie's attempt to give the Arthur Conan Doyle stories a gangland makeover.

The as yet untitled Baron Cohen film will also have a new take on the Holmes stories featuring the London-based detective, according to film trade magazine Variety.

Madonna's husband's film is said to have the backing of Warner Bros, while the Baron Cohen movie comes from Columbia Pictures.

Columbia Co-President Matt Tolmach was quoted in Variety as saying: "Just the idea of Sacha and Will as Sherlock Holmes and Watson makes us laugh.

"Sacha and Will are two of the funniest and most talented guys on the planet, and having them take on these two iconic characters is frankly hilarious."

Baron Cohen, 36, and comedy star Ferrell, 40, worked together two years ago on Talladega Nights, in which they played rival racing car drivers.

Basil Rathbone played Holmes in 14 films between the 1930s and 1940s, and Jeremy Brett in the TV series in the 1980s and 1990s.

British star Baron Cohen's film career so far has included a role this year in the Tim Burton musical adaptation of Sweeney Todd.

He played a rival singing barber who meets a bloody end at the hands of Johnny Depp's Todd.

The comedian, who recently became a father for the first time when actress fiancee Isla Fisher gave birth to their daughter Olive, has also been filming scenes for the latest of his mischief-making comedy creations.

Gay Austrian character Bruno follows in the footsteps of Ali G, the wannabe rapper from Staines, and Borat, the anti-Semitic and homophobic reporter from Kazakhstan.

Bruno: Delicious Journeys Through America For The Purpose Of Making Heterosexual Males Visibly Uncomfortable In The Presence Of A Gay Foreigner In A Mesh T-Shirt is out in October.

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