Lily James has become a mountain-climbing "addict" since filming the Cliffhanger reboot.

The Cinderella star, 36, leads the cast of a new version of Sylvester Stallone's 1993 action movie alongside Pierce Brosnan and the actress has confessed she had the "had the time of [her] life" working on the film and she's thrown herself into the sport of climbing.

She told The Hollywood Reporter: "Oh my God, I had the time of my life. It was so hard. I did five hours of climbing a day for many weeks.

"I was on mountains nonstop. I fell completely in love with it. It's the most mind-body-soul activity.

"And I'm a [mountain-climbing] addict now. I did all my own climbing [in the film], and I got real strong. I was just pounding press-ups between every take."

The film is due for release next year and Lily can't wait to share it with audiences.

She added: "I'm really proud of Cliffhanger. I'm so excited. We're in the edit and getting it ready, and I'm super hopeful.

"It is such a cool reimagining, and while it's really unexpected at times, it keeps all the gripping glory of the original, I hope."

Lily went on to reveal she loved working with Brosnan again after they previously appeared in 2018 movie musical Mamma Mia! Here We Go Again.

She said of her co-star: "We were so lucky to have him, and he's so brilliant in the movie. He's one of life's true gentlemen, and he was such a brilliant actor to have as our father in this story.

"He just brings real heart, and he elevates the whole thing. He's just a dream, and getting to work with him again was so wonderful."

Lily plays Naomi Cooper in the new film with Brosnan as her onscreen dad - and the actress previously insisted the new take is "definitely different" to the original.

Speaking with Screen Rant, she said: "I don't want to say too much to give it away right now. What I will say is I had one of the most thrilling experiences of my life. We shot in the Dolomites. We were there for six weeks on the mountains.

"I was really hanging off mountains. We had to shut down multiple times because of freak snowstorms.

"The story is very much through Naomi and her sister Sydney. I would hope that we are maintaining what people love about the original cliffhanger, but it's definitely different.

"It's feral, it's raw. It's a real re-imagining, and I am producing it too."

Stallone was initially due to reprise his role as ranger Gabriel 'Gabe' Walker in the new Cliffhanger movie, but the actor ultimately left the project and it was subsequently overhauled with James and Brosnan leading the reboot instead.

The official synopsis reads: "In this reboot of Cliffhanger, seasoned mountaineer Ray Cooper (Brosnan) and his daughter Sydney run a mountain chalet in the Dolomites.

"During a weekend trip with a billionaire's son, they are targeted by a gang of kidnappers. Ray's older daughter Naomi (James), still haunted by a past climbing accident, witnesses the attack and escapes."

The cast for Cliffhanger also includes Nell Tiger Free, Franz Rogowski, Shubham Saraf, Assaad Bouab, Suzy Bemba and Bruno Gouery.