Geoffrey Rush thinks 'The King's Speech' is a "bromance" movie.

The Australian actor - who plays therapist Lionel Logue in the movie about Britain's King George VI and his prohibitive speech impediment - believes the movie is how a platonic romance developed between the two despite their very different backgrounds.

He said: "What fascinates me about this story is that you have the most unlikely meeting of two people, an imperial figure and a colonial nobody - and they find Common ground.

"We started calling it a bromance about half way through."

Firth, who portrays the former king, believes getting the stutter right was imperative to the success of the movie, which has been an early frontrunner for predicted Oscar nominations.

He told USA Today: "You got to feel the pain in this, but not so much that people say, 'I've got to get out of the cinema.'

"You've got to get the idea across that it takes this guy an hour to get a word out. But you only have a 90-minute film. You've got to try to establish this by stealth."