Colin Firth decides on 'conscious uncoupling' with 'Paddington' after failing to capture voice
Oscar winner says he has come to the 'sad realisation' that he can't do cartoon bear justice
Firth was due to voice the popular character, known for his love of marmalade sandwiches, alongside Nicole Kidman, pictured right, who has signed up to play the villain of the piece.
In a statement given to Entertainment Weekly confirming his departure, Oscar winner Firth said: "After a period of denial, we've chosen 'conscious uncoupling. It's been bittersweet to see this delightful creature take shape and come to the sad realisation that he simply doesn't have my voice.
He continued: "I've had the joy of seeing most of the film and it's going to be quite wonderful. I still feel rather protective of this bear and I'm pestering them all with suggestions for finding a voice worthy of him."
Other cast members in the big screen adaptation of Michael Bond's classic character include Julie Walters who will appear as Mrs Bird, housekeeper to Paddington's adoptive family the Browns. Meanwhile, Hugh Bonneville (Downton Abbey) and Sally Hawkins (Made In Dagenham) have been cast as Mr and Mrs Brown.
The Paddington Bear film is being produced by David Heyman, who helped bring the Harry Potter books to the big screen, while Paul King (The Mighty Boosh, Bunny And The Bull) is on board as director. It will open in UK cinemas on November 28, 2014. See the film trailer below.