Discussing her later roles in film and television, Dame Maggie told ES Magazine: “I am deeply grateful for the work in (Harry) Potter and indeed Downton (Abbey) but it wasn’t what you’d call satisfying.
“I didn’t really feel I was acting in those things.”
Actor Hugh Bonneville, who played the son of Dame Maggie’s character in Downton Abbey, said in a statement: “Anyone who ever shared a scene with Maggie will attest to her sharp eye, sharp wit and formidable talent.
“She was a true legend of her generation and thankfully will live on in so many magnificent screen performances.
“My condolences to her boys and wider family.”
Dame Maggie remained among the Downton Abbey cast until the series came to an end in 2015, and reprised the role for two films in 2019 and 2022.
Throughout her celebrated career, she was also awarded five Baftas, three Golden Globes, five Screen Actors Guild Awards, two more Emmys and a Tony Award.
She was appointed a CBE in 1970 and was made a dame in the 1990 honours list for services to the performing arts.