Rachel McAdams is set to play Irene Adler, opposite Robert Downey Jr's 'Sherlock Holmes' according to the Hollywood Reporter.
The character she plays appeared in Doyle's 1891 "A Scandal in Bohemia." The actress' deal calls for her to return for sequels as well.
The new movie is to be a reimagining of the classic detective based on a hypothetical graphic novel created by producer Lionel Wigram. Guy Ritchie is directing for Warner Bros. and Village Roadshow.
Also cast are Mark Strong ('RocknRolla') plays the main villain, Blackwood and Jude Law as Dr. Watson.