The 43-year-old actress, who is best known for her roles in Charlie's Angels, Kill Bill and Kung Fu Panda, will star opposite Jonny Lee Miller in Elementary, a new spin on the original story of the London-based consultant detective.
According to The Hollywood Reporter, this will be the first time that a woman has played Sherlock Holmes's sidekick.
The character of Watson was most recently portrayed by Jude Law on the big screen and by Martin Freeman in the BBC's take on Sir Arthur Conan Doyle's detective novels.
Other actors such as Ben Kingsley, Dudley Moore, Robert Duvall and James Mason have also previously played the part.
Elementary has previously been described as a modern-day take on Sherlock Holmes set in New York.
Sue Vertue - a producer of the BBC's Sherlock starring Benedict Cumberbatch - recently issued a warning to Elementary bosses, saying: "We have been in touch with CBS and informed them that we will be looking at their finished pilot very closely for any infringement of our rights."
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> 'Sherlock' executive Sue Vertue 'extremely worried' by 'Elementary'