Warner Brothers said the sequel would debut in mid-December of 2011, reuniting Downey, Jude Law as Dr. John Watson and Rachel McAdams as Irene Alder, Variety reported Friday.
The first "Sherlock" installment, based on Sir Arthur Conan Doyle's sleuth, hit theaters Christmas Day.
Downey won a Golden Globe for his performance.
Guy Ritchie, who directed the first film, will likely direct the second, which is expected to start production this summer.
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