In Grandma, Lily Tomlin, takes a rare lead film role as a foul-mouthed hippy lesbian poet and yes, grandmother.
The role draws on the American actor's own free-wheeling personality, her experience as an outspoken feminist, and the fact that she is gay.
She's played many heterosexual partners and wives - including her Emmy-nominated role on Netflix series Grace and Frankie.
She says of her own 44-year relationship with writer-producer Jane Wagner: "Nobody cares or asks about it really. We were married last year, something my character in Grandma was never able to do."
Director Paul Weitz (About a Boy) had so loved Tomlin in his previous film, Admission, that he wrote Grandma especially for her.
"After hanging out with Lily I realised how smart she is," he says. "I just wanted to see a movie where she was in every scene."
Shot in 19 days, Grandma has Tomlin, still reeling from the death of her longterm partner, driving around in her broken-down car, seeking funds for an abortion for her naive granddaughter, Sage (the angelic Julia Garner), and giving her advice along the way.
"Elle is a woman in her early 70s who's much edgier than her granddaughter," Tomlin explains. "She can't stand injustice, she can't stand to be discriminated against and she's disillusioned because the feminist movement didn't make the progress she would have liked. Her granddaughter is almost like a throwback to the 50s and a lot of young women today are in that place. Sage learns a lot from her grandmother and Elle changes too.
"I hope it isn't a polemic of any kind but I'm glad that it talks about how things build up over time and separate people, and how there is a way to make peace in the end."
Tomlin enjoyed working on the low-budget independent production, in which she wore her own clothes and brought along the old Dodge she drives in the film.
"The car is almost a character in the movie," says Tomlin. "I knew I kept that car for a reason."
Judy Greer, the mum in Jurassic World, plays Elle's younger lover in Grandma. "I really wanted to work with Lily," she says. "Lily's an icon and I would have done any role in this movie if it was with her.
"Elle's strong but emotional and I like that she's not whining or crying or begging. She's trying to reason with someone she loves and it can be difficult. And I always love a break-up scene!"
In Grace and Frankie Tomlin and Jane Fonda are good friends whose respective husbands - Sam Waterson and Martin Sheen - have left them after announcing to their wives they have been in a relationship for 20 years.
And she's still a stage regular with her own one-woman show playing a bunch of characters.
Weitz: "We wrapped shooting on Friday and on Saturday evening she gave a two-hour performance ... I didn't know where she got the energy but it was kind of humbling."
Who: Lily Tomlin
What: Grandma at the New Zealand International FIlm Festival on July 21 and July 25; Grace and Frankie on Netflix.