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OTRC: Rachel McAdams dishes on 'fun' relationship with Robert Downey Jr. in 'Sherlock Holmes'

Rachel McAdams talks 'Sherlock Holmes: A Game of Shadows.' (Warner Bros. Pictures)

Rachel McAdams returns to the big screen in "Sherlock Holmes: A Game of Shadows" and the actress said she had "fun" working out her relationship with her character and Robert Downey Jr.

"The relationship between Robert and I is fun, that's a fun dance and getting the pitch of that just right," Adams said in an interview provided by Warner Bros. Pictures. "It can be quite playful and then there's drama and danger and all the good stuff."

"You know there's always a bit of holding back -- kind of a cat and mouse game and who is going to reveal their feelings first or how much," she added about their character's love story. "And then there's the other plot going on -- what she is keeping from him or vice versa that they need to actualize other goals."

The first "Sherlock Holmes" film introduced the main characters, detective Sherlock Holmes (played by Downey Jr.) and his sidekick Dr. John Watson (portrayed by Jude Law) Rachel McAdams starred as Holmes' love interest, Irene Adler.

The sequel has Holmes and Watson investigating the death of the Crown Prince of Austria and is set for release on December 16. The detective and Watson travel the world to try and stop the evil Professor James Moriarty (Jared Harris) and the two team up with a Gypsy named Sim (played by Noomi Rapace). McAdams reprises her role as Adler.

"She is just very different from other characters that I've played," McAdams said about Adler. "She can be quite cheeky and she's always got something up her sleeve, so there's lots going on behind the curtain," she said.

The actress added, "I'm confused by her at times in her mystery."

As for the evil Moriarty played by Harris of "Mad Men" fame, McAdams said the actor is "really lovely. You know, he's not at all like Moriarty."

"So it's really exciting to him turn that on when the cameras were on and he's quite intimidating," she added. "I think he makes a great Moriarty."

"Sherlock Holmes: A Game of Shadows" is slated for release on December 16. Watch a trailer below.

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