Jim Broadbent and Brenda Blethyn will play Raymond Briggs' parents in an animated adaptation of one of The Snowman author's best-selling books.
The duo will take on the title roles in the film version of Ethel And Ernest which tells the story of the couple's life through four decades of marriage taking in the Great Depression, the Second World War and the swinging 60s.
Briggs said: " My mother's reaction would no doubt have been, 'Oh, Ernest! We're going to be on the pictures! We might even be at the Odeon in Wimbledon!'."
Luke Treadaway, who won plaudits for his performance in the stage version of The Curious Incident Of The Dog In The Night-Time, will play Briggs and the cast a lso includes Born Free star V irginia McKenna, Pam Ferris and EastEnders veteran June Brown who has played Dot Cotton in the soap since its early days.
Director Roger Mainwood said: "It's a real privilege to be directing the feature film of Ethel and Ernest, which many consider to be Raymond Briggs' masterpiece.
"Time will tell if the end result does the book justice, but so far Raymond has loved everything he has seen. We are also delighted with the quality of the voice cast. Brenda and Jim are absolutely bang on as the title characters and the other actors bring an enormous amount of charm and character to their roles."
Blethyn said: " I adore working with Jim Broadbent. We've worked together before and it's great to come back together to play these wonderful characters. They lived through two wars and it's so, so reminiscent of my own parents' life in so many ways. Ethel even looks like my mum!"
The film, which will be shown on the BBC, is set for release next year.