Helena Bonham Carter is to portray Britain's Queen Mother in a new film. The "Harry Potter" star is in negotiations to play the royal matriarch in "The King's Speech," a movie about how Elizabeth helped her husband - King George VI - overcome his stammer.

"Dorian Gray" actor Colin Firth and "Pirates of the Caribbean" star Geoffrey Rush have signed on to appear in the film, which will be directed by Tom Hooper.

Firth is convinced Helena would be "sublime" in the role.

He told Britain's Daily Mail newspaper: "The film takes place before she took on the cuddly Queen Mum mantle, when she was much younger, making Helena ideal."

"This was when her husband - then the Duke of York - was going through the Abdication crisis and had to prepare himself for public speaking."

The film starts shooting in London later this year and is expected to be released late next year.