Robert Downey Jr has revealed he and Jude Law have a similar connection off screen to their characters Sherlock Holmes and Dr Watson on it.
The pair are reunited in Guy Ritchie's Sherlock Holmes: A Game Of Shadows, the sequel to the 2009 box office smash, where the sleuthing duo take on new criminal mastermind Professor James Moriarty (Jared Harris).
The winning connection between Holmes and Watson is reflected in the close friendship the two actors have forged off-screen.
Downey Jr said: "I feel about Jude the way Sherlock feels about John; I love the guy like a brother. I couldn't ask for a better partner."
The pair put in additional hours together on their days off, honing their characters and rehearsing scenes. And the result? Palpable on-screen chemistry.
As Ritchie said: "The bread and butter of this movie is always going to be the relationship between Sherlock and Watson, and you can't really have enough of those two and their camp banter."
In return Downey Jr said he had huge admiration for the director.
"I love working with Guy; it's such a collaborative process and he has a terrific sense of humour that really comes into play.
"On this film, there was an element of rediscovering Sherlock Holmes all over again. We wanted to maintain that sense of fun but with even more gravitas."
:: Sherlock Holmes: A Game Of Shadows is in cinemas now.