Guy Ritchie had doubts about the first 'Sherlock Holmes' movie.

The 42-year-old director - who is taking the helm of the second film in the franchise 'A Game of Shadows' - admits when he shot his first film adaptation of Arthur Conan Doyle's fictional detective book series, he wasn't confident about the acting abilities of stars Jude Law and Robert Downey Jr..

Referring to the sequel, Guy - who saw the first movie succeed at the box office - told Empire magazine: "I think we're more confident that we were on the last one. I certainly feel that. I feel certainly more confident that these two can act, which I was f***ing dubious about the first time round!

"I think we hit the ground running on this one. But we knew what we were doing."

Jude - who portrays the protagonist's sidekick Dr. Watson in the two movies - admits there was a lot of "dancing around" with his co-stars on the first shoot as they tried to figure each other out whereas everyone was ready to get to work on the sequel.

He explained: "Although we immediately got on, there was a certain amount of dancing around, working each other out. This time it was, 'Great, let's go.' "