Gwynne also recently appeared in season 5 of 'The Crown' as controversial royal Lady Susan Hussey.
English actress Haydn Gwynne has died at age 66.
In a statement to the BBC on Friday, Gwynne's agent said: "It is with great sadness we are sharing with you that, following her recent diagnosis with cancer, the star of stage and screen Haydn Gwynne died in hospital in the small hours of Friday 20 October, surrounded by her beloved sons, close family and friends. We would like to thank the staff and teams at the Royal Marsden and Brompton Hospitals for their wonderful care over the last few weeks."
The Olivier and Tony-nominated actress was set to appear in a new production of Stephen Sondheim's Old Friends at London's Gielgud Theatre, however she withdrew from the role in early September -- just a week before previews were to begin -- citing "sudden personal circumstances" at the time.
Following the news of her death, the show's Instagram account shared a tribute to the late actress, dedicating Friday night's show to her memory.
"The tragic news that the much loved actress, Haydn Gwynne, has died this morning after a very short illness is an enormous shock; even to those of us involved in Sondheim’s musical celebration Old Friends at the Gielgud, who already knew she was ill and forced to leave rehearsals for a show in which she already had a sensational success at its Gala Premiere last year, stopping the show singing The Ladies Who Lunch," producer Cameron Mackintosh said in a statement. "Haydn was a truly wonderful person, as well as a phenomenally talented actress and singer, so it is a double tragedy for everyone to be deprived of both her spectacular talent and her company so abruptly."
Gwynne got her start acting in her mid-20s, in various television roles. She was nominated for a BAFTA in 1992 for her role as Alex Pates in Drop the Dead Donkey. She also found success on the West End, earning four Olivier nominations over the course of her career, including one for originating the role of dance teacher Mrs. Wilkinson in Billy Elliot the Musical.
She continued the role as Billy Elliot moved to Broadway, earning her a Drama Desk Award and Tony nomination for the performance.
In recent years, she played Camilla, Duchess of Cornwall, in The Windsors, a comedy spoof of the royal family. She also appeared on season 5 of The Crown, playing a controversial royal, Lady Susan Hussey.
Gwynne is survived by her two sons.