Hattie Jacques appearing in the BBC's Sykes sitcom 1978
Gavin and Stacey star Ruth Jones is to play Carry On comedy actress Hattie Jacques in a drama about her love life.
Hattie will focus on the star's secret affair with a younger man while married to John Le Mesurier of Dad's Army fame.
Jones, best known for playing brash Barry girl Nessa in Gavin and Stacey, which she co-wrote, said Jacques was someone she could not wait to play.
The actress said Jacques, who died in 1980 from a heart attack, was "so much more than just the 'funny fat lady'".
Jacques appeared in 14 of the innuendo-laden Carry On comedy classics, where her physical stature meant that she was often cast as matronly characters.
She was also known for her long on-screen partnership with comedian Eric Sykes in his sitcom Sykes.
Her career took off when she appeared first on radio show It's That Man Again in the late 1940s, and later on other hugely popular shows like Hancock's Half Hour, with Tony Hancock, and Educating Archie.
She also appeared in two Norman Wisdom films, before her roles in the Carry On series between 1958 and 1978.
Married to John Le Mesurier, she had an affair with car salesman John Schofield - he moved into their home and Le Mesurier moved to another room in the house.
They divorced in 1965 and then Schofield left her after meeting someone else while visiting Jacques in Rome.
Ruth Jones said she "can't wait' to play Jacques, one of her heroines
As well as starring and co-writing the award-winning comedy Gavin and Stacey, Jones also recently played Tess of the D'Urbervilles' mother in the BBC1 adaptation.
Jones said of Jacques: "She was an incredibly talented and fascinating woman both on and off screen and so much more than just the 'funny fat lady'."
The one-off drama, to be screened on BBC4 later this year, has been written by Stephen Russell, who has also worked on Shameless.
Other leading roles have still to be cast for the production which will be filmed in Glasgow by production company Angel Eye Media.
Executive producer Jemma Rodgers said: "The drama has a wonderfully warm heart and takes us behind the scenes of the public face of Hattie Jacques to reveal her unconventional but very modern relationships."