LOS ANGELES, Oct 30 — Linda Hamilton set a new standard for female action heroes more than 30 years ago, but her return to the Terminator movie franchise prompted more than a little soul searching.

Hamilton, 63, reunites with Arnold Schwarzenegger and director James Cameron for Terminator: Dark Fate, out in US movie theatres on Friday.

"I sort of had an existential crisis at the beginning of the film when I showed up and felt like 'uh-oh,'” said Hamilton. "I've never felt more alone in my life than when I started and that probably wasn't a reflection to what was going on on set and around me. It was what was going on inside of me,” the actress said.

Set two decades after Hamilton played Sarah Connor as a muscular mother battling futuristic cyborgs to save her teenage son in 1991 film "Terminator 2: Judgment Day, the new movie sees her teaming up with an enhanced human to save a Mexican factory worker from a terminator from the future.

Hamilton said she trained her body for a year for the role as well as "getting myself into Sarah's head, her disappointments, her sorrows, her guilt, all the deep hard stuff.”

The actress, who was married to Cameron from 1997 to 1999, shrugged off the acclaim she won for her earlier work as Connor, which led the way for the portrayal of strong women on screen.

"That's just an actress playing a part and it's an accident of timing. It's not that I didn't do good work. It was that the world was ready to receive it too. So, I try to stay very, very balanced about it and never think of myself as an icon or having a legacy,” she said.

So balanced that Hamilton said she was looking forward to returning to what she called her "invisible” life at home in New Orleans.

"When this movie's open, I'm just going to, like, go underground, be invisible for a while,” she said.

"I don't want to be that person in my neighbourhood. I want to be like, 'Let's talk about our dogs and our cats and the people around us being born.' ... I've established a very real, authentic life for myself and I don't want that to change when I go home to it.” — Reuters