Park City, Utah - Packed full of nail-biting chases, hi-tech gadgets, and an armed standoff, Thelma could be the next Mission: Impossible movie – except its star, June Squibb, is 94.

In the film, Squibb's hero takes matters into her own hands after she is swindled into sending $10,000 to a scammer, racing across Los Angeles on a souped-up mobility scooter with a dusty old gun, determined to confront the villain.

Remarkably, the action-comedy, which premiered at the Sundance festival on Thursday, is the first leading film role for the veteran stage actor, who earned an Oscar nomination for Nebraska a decade ago.

So how does it feel to become Hollywood's hottest new action star in her twilight years?

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"It feels great! I love it! Me and Tom (Cruise)!" Squibb told AFP.

Indeed, the film is littered with references to Tom Cruise, whose films her character Thelma enjoys watching with her grandson.

It plays with tropes from the Mission: Impossible films, such as a top-secret mission briefing delivered through a hearing aid. Cruise himself signed off on the use of footage from his movies.

"I said, 'Is he letting us do this?' And they said, 'Sure, they like it!'" recalled Squibb.

Squibb also took more personal inspiration from the Hollywood A-lister – including his famous insistence on doing many of his own stunts.

"They told me, 'Slow down June, don't go so fast!'" she said, of a chase sequence on her mobility scooter which required a collision.

"I thought, 'This is silly,' and I just rammed right into him and then took off down the hall. And they got that all on camera."

The movie's colorful premise and stars – including the late Richard Roundtree, and Malcolm McDowell – have it already tipped as one of the "buzziest" titles at this year's Sundance festival, which champions independent filmmaking.

But it has a personal and poignant message for its director Josh Margolin, who named the film after his own grandmother Thelma, now 103.

She was tricked by a scammer into believing he had been in a car crash and needed bail money.

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Thankfully, the real Thelma did not part with any money before his family rumbled the scheme, but the incident got Margolin thinking about what would have happened if she had sought justice – "something that I would not put past her!"

"Watching Tom Cruise jump out of a plane is just as scary as watching my grandma jump onto a bed," he said.

"It's smaller, but for her at this moment in her life, and where she's at, that presents real danger, and is nerve-wracking to watch."

"So I wanted to shrink those tropes down to explore her strength, her tenacity, her determination."

The movie also examines how society often underestimates the elderly, and how as a grandson Margolin may "feel the urge to over-protect" out of love, even when his grandmother "is more capable than I give her credit for."

While the stubbornly independent fictional Thelma enjoys living alone and is determined to keep doing so, her silver-haired partner-in-crime Ben (played by Roundtree in his final role) has embraced the support of his care home.

It is a debate that Squibb can relate to.

"I'm always pleased when I'm involved in something that makes a statement about age," she said.

"I'm alone, and I don't get lonely. I really don't. I'm sort of, 'Oh boy, I can just sit by myself and do what I want!'" she added.

Squibb also continues to work, with upcoming projects including an American Horror Stories series, and a film directed by Scarlett Johansson called Eleanor, Invisible.

After decades in which Hollywood was famously reluctant to give roles to even middle-aged actresses, Squibb believes that is finally changing.

"And I thank God for it!" she said, expressing hope that her own film will find a distributor at Sundance and eventually end up in theaters and on streaming.

Could there even be another Oscar nomination in store at last?

"Well, that would be lovely," she said. "It was fun."