In full flow, Lily Tomlin is telling an anecdote about going to that once-famous Hollywood eatery Perino's. "I'd heard about it all my life through movie magazines," she says. "All the stars would go there." Tomlin's time finally came after making her breakthrough in television sketch-show Rowan & Martin's Laugh-In in 1969.
"I was popular in that hot way you are when it first happens," she shrugs.
She decided to go with her brother and her manager. But when the waiter brought her a disappointing starter, she refused to pay the bill. To cut a long story short, the waitresses called her a "troublemaker", the chef came out from the kitchen slapping a piece of meat, proclaiming it was "the best veal in town", and, finally, a motorcycle cop arrived to sort out the escalating farce. And all for what? $5.50 knocked off her bill.
This is a typical Tomlin tale - rich and relatable. In her new film, Grandma, she plays Elle Reid - a gay poet and troublemaker. In one scene, she causes a stir for talking loudly about her granddaughter's impending abortion in a coffee shop.
Written and directed by Paul Weitz (About a Boy), it was penned with Tomlin in mind. The actress has her own moments of volatility - judging by the infamous video of her foul-mouthed rant on the set of David O Russell's I Heart Huckabees.
"The fact that she's really scathing and at the same time utterly kind [inspired the character]," Weitz tells me.
"When I first gave her the script, she said to me, 'this character is angry a lot of the time, I'm not sure I understand her temper'. And then she paused and said, 'I know you've seen this video of me yelling at David O Russell, but that's not the way I am'. Then she proceeded to tell me lots of other instances in which she'd chewed somebody out."
In person, Tomlin's anything but angry. At 76, she's not your typical grandmother either; stage, screen, stand-up - there isn't a medium, really, that she hasn't conquered. Not bad for a girl from Detroit, the daughter of a factory worker and nurse's aide.
She recalls being on a chat show, telling the host: "Listen, where I came from, parents were successful if the girl didn't get pregnant and the boy didn't go to the slammer! That was all I had to avoid."
After studying biology at Wayne State University in Detroit, Tomlin wound up auditioning for a play at a friend's suggestion, and before long was doing the rounds on the Detroit comedy circuit. Moving to New York, she was picked up for Laugh-In and her career blossomed. Over the years, she has scored a Golden Globe, a Grammy for best comedy recording and a Tony for her performance in Broadway show The Search For Signs of Intelligent Life in the Universe, along with a clutch of Emmys. She just needs the Oscar to complete the set.
There's talk Tomlin could be up for a shot with Grandma; her only other nomination was in 1976 for her turn in Robert Altman's stunning country-music ensemble film Nashville.
The film, which sees Elle spend the day trying to raise the $600 needed for her granddaughter Sage's (Julia Garner) termination, is unsensational in the way it portrays issues like abortion or sexuality.
"I think it's progressive," says Tomlin. "Just being pro-choice and tossing it off, instead of hammering away at a subject, or being righteous about it."
Much of the humour comes when Elle's estranged daughter - played by Marcia Gay Harden - arrives.
"It's really about the choices of these three women, this three generations of women, and their relationship."
Given Tomlin is gay, was it significant for her to play that?
"It was nice that I was gay, that I was playing someone of an age who could've lived all those things," she nods.
It's not the first time - on stage, she has played gay characters and she was a "gay archaeologist" in Tea With Mussolini, a film with Judi Dench. For years, Tomlin has been together with writer Jane Wagner, but she hid her sexuality for fear of offending her mother.
Did she ever feel pressure to come out? "No," she replies. "I would've had to call a press conference and made a big announcement - and it was just too corny. Everybody that I talked to, in the industry or journalism, they knew that I was gay, but they just didn't write about it as much then."
How much has the film industry shifted since her early days?
"It's changed tremendously. Some for the worse, definitely. I suppose some for the best."
She talks about actresses now "creating their own myth", in league with stylists, fashion houses and magazines.
"The group shots of powerful young actresses ..." she shudders. "They have to build up a lot of material to keep the interest of the public going."
At least, she concedes, those young actresses are currently keeping the "hot topic" of pay inequality hot. Recently, Tomlin's television show Grace and Frankie entered the debate, when it was revealed that she and Jane Fonda, who play the leads, earned the same as supporting male co-stars Martin Sheen and Sam Waterston.
This aside, Tomlin is very happy to be involved with Grace and Frankie, having just completed the second season, and working with old friend Fonda. Maybe they should reunite with Dolly Parton - their co-star from the 1980 workplace comedy Nine to Five, one of the biggest hits of Tomlin's career?
"I know," she nods. "Everybody has been after us for that. Jane and I think we've devised a way to get her into the third season."
Tomlin still does stand-up, but it's getting a bit much. Does she ever feel like just calling time on her career?
"Some days I do," she sighs, gazing at the Soho skyline. "I see so many damn cranes in this city," she says, switching topics. It feels like she doesn't want to talk about retirement. That's just for grandmas, right?
Grandma is at cinemas now