The actor revealed in an interview with MTV News that playing Sherlock Holmes was his biggest challenge to date.
Downey Jr., who stars as the English detective in the upcoming Guy Ritchie film, struggled more with playing the infamous sleuth than when he recently did his Iron Man stint. "Sherlock Holmes is easily the toughest job I’ve ever had," he confessed.
The character, created by Sir Arthur Conan Doyle, is portrayed as having a great sense of foresight and concentration. "He thinks through all eventualities, possibilities and counterattacks when he’s fighting, so he actually has the fight worked out before he starts," the actor explained.