Former Skins star Kaya Scodelario said filming the sequel to the Maze Runner was like "waking up with a hangover every day".
Scodelario, who stars as Teresa in the Maze Runner: The Scorch Trials, was referring to hours spent filming at a high altitude in New Mexico.
"It feels likeyou wake up with a hangover every single day," Scodelario explained. "But it's beautiful. The landscape is really important to the movie, it's so vast."
She and her co-stars, Thomas Brodie-Sangster (Newt), and Ki Hong Lee (Minho), surprised fans at a special screening of the film in London's Leicester Square.
Kaya Scodelario stars in Maze Runner: The Scorch Trials.
They also starred in the first film, 2014's The Maze Runner, alongside lead Dylan O'Brien, who plays Thomas.
A select group of 200 fans won the chance to attend the screening.
Scodelario said she'd closely watched the competitions: "I've seen a bunch of stuff. They're amazing. They're so on it with social media, it's really impressive."
In the sequel, their journey takes them to the Scorch - a desolate landscape filled with dangerous obstacles.
They team up with resistance fighters to take on the powerful WCKD, and uncover the organisation's shocking plans.
Brodie-Sangster, who has previously starred in a Game of Thrones and Love Actually, said: "We were 5000 feet above sea level and we were filming in the mountains. The lack of oxygen up there is really quite something."
Dylan O'Brien stars in Maze Runner: The Scorch Trials.
Director Wes Ball revealed it was a bit of a shock taking on the new landscape: "Filming for the first film was flat and humid and full of bugs. Now we're in this mile-high city with a big change in atmosphere.
"Shooting in these crazy environments of sand and rock and rusty metal was a completely different environment for us, but it adds to the movie in a really cool way."
Maze Runner: The Scorch Trials is released on September 10.
