Watch Sherlock Holmes 2009 Full Movie Online. Sir Arthur Conan Doyle's famous super-sleuth, Sherlock Holmes, gets an update with this adaptation of Lionel Wigram's comic book series by writer/director Guy Ritchie (RocknRolla) starring Robert Downey Jr. as the titular detective, with Jude Law stepping into the shoes of his sidekick, Dr. Watson. Heading up the rest of the cast are RocknRolla's Mark Strong as the film's villain, Blackwood, and Rachel McAdams portraying the love interest, Irene Adler.