Downey can now be seen in the summer blockbuster "Iron Man." He previously starred in "The Pick-Up Artist," "Less than Zero," "Chaplin," "Only You," "Gothika," "Kiss Kiss, Bang Bang" and "A Guide to Recognizing Your Saints."
Ritchie, who is Madonna's husband, is to start filming "Sherlock" in October with Downey as the picture's titular detective, Variety.com reported.
Based on Arthur Conan Doyle's classic stories, as well as the comic book "Sherlock Holmes," the new movie is to be produced by Joel Silver, Lionel Wigram, Dan Lin and Susan Downey, Robert Downey Jr.'s wife, the entertainment industry trade newspaper said.
2014: The Year in Music [PHOTOS]