Jamie Lee Curtis had been "waiting her whole life" to work with Ella McCay writer-director James L. Brooks.

The filmmaker's latest drama stars Sex Education's Emma Mackey as the titular character, a 34-year-old lieutenant governor who has to tackle a series of family issues while preparing to take over from the state's longtime incumbent governor.

Halloween star Curtis, who plays Ella's confidante and mother figure, Aunt Helen, couldn't resist saying yes to the role when Brooks offered it to her in a handwritten letter.

"I actually got a handwritten letter from James L. Brooks," she said at a screening of the film in London this week. "It said, 'Jamie, I've taken a long time to write this script. I'd love you to play Helen. We shoot in the fall. I direct better than I handwrite, Jim.'

"Now, I'm 67 years old, I've been waiting my whole life for a letter from James L. Brooks. My whole life and career to have a director who I admire as much as I do Jim write me a letter saying he'd like me to play a part in a movie. It's just been an incredible experience."

Brooks is known for making films including Terms of Endearment and As Good as It Gets, and producing The Simpsons. Before Ella McCay, he hadn't written and directed a film since 2010's How Do You Know.

Curtis and Mackey added that they felt "lucky" to work with Brooks, 85, as well as their co-stars Jack Lowden, Woody Harrelson, Rebecca Hall and Kumail Nanjiani.

The political comedy-drama will be released in cinemas on 12 December.