Downey Jr reprises his role as Sherlock Holmes in Guy Ritchie's Sherlock Holmes: A Game of Shadows about the well-known English detective and his partner Dr. John Watson (Jude Law).
When he was asked on Jimmy Kimmel Live! if he keeps up with his accent off-camera, Downey Jr joked: "I am not a method actor. I am a lazy person."
Downey Jr then shared that his long-time dialect coach helped him with his accent.
"I have a really great dialect coach that I've known since Chaplin and he just drills it into me," he said and added that he became "fairly good at dialects" to avoid being "ridiculed".
He also said that he will take as much time off as he can, since he is expecting a baby boy with wife Susan Downey.
Watch the trailer of Sherlock Holmes: A Game of Shadows below: