Armie Hammer isn't nervous about kissing Leonardo DiCaprio in new movie 'J. Edgar'.

The actor will play Clyde Tolson - an associate and rumoured gay lover of Leonardo's character, FBI director John Edgar Hoover - in the Clint Eastwood-directed biopic but says he isn't worried about the scenes because he knows they're important to the film.

He told E! Online: "It's not a kissing scene. It's a ton of kissing scenes. I actually just met him for the first time Saturday at the DGA Awards.

"He's a talented actor. I'm not nervous or afraid of it being awkward. The Script is great. The scenes are in there for a reason."

As well as Armie and Leonardo, Naomi Watts will star as Hoover's secretary of 54 years Helen Gandy, who after his death destroyed his personal file containing incriminating material that he used to control powerful political figures.

Dame Judi Dench is set to star as Hoover's mother, while 'Gossip Girl' star Ed Westwick is also part of the cast.

The film is set to be released at the end of 2012.