Robert Downey Jr., riding high at the box office with “Iron Man,” is in final negotiations to play Sherlock Holmes in director Guy Ritchie’s movie about the super sleuth.

The Warner Bros. project, dubbed “Sherlock Holmes,” will have to contend with a rival movie at Columbia, a comedy starring Sacha Baron Cohen.

Ritchie’s version takes its cue from a forthcoming comic book that producer Lionel Wigram wrote as a selling tool for a new take on Sir Arthur Conan Doyle’s classic character. The concept sees Holmes as more adventurous and less stuffy than previous screen incarnations and mines more obscure character traits.