Viggo Mortensen "couldn't breathe" while filming a diving scene in Ron Howard's latest movie 'Thirteen Lives'.
The 63-year-old actor stars as British civilian cave diver and rescuer Rick Stanton in the biographical survival film about the 2018 Tham Luang cave rescue, which saw a junior football team and their coach trapped in a cave for a period of 18 days.
And the 'Lord of the Rings' star had to train to dive for the tough underwater sequences to recreate the moment 12 people got stuck inside the Thai cave.
Real-life Rick and Viggo discussed his experience over Zoom so he was prepared for the scenes.
And while filming in one of the makeshift caves on set in Australia, one of his oxygen tanks stopped working and he couldn't breathe for a few seconds.
In the new issue of People magazine, Viggo recalled: "All of a sudden I couldn't breathe.
"It seemed like a long time, but it was only a matter of seconds. I panicked."
Fortunately, he remembered what Rick had told him to do in that situation.
He said: "It's not that complicated. But at the moment, it's hard to think clearly."
Viggo has had a number of close-calls on movie sets, including nearly being dragged to the bottom of a river while shooting 2002's 'The Lord of the Rings: The Two Towers', in which he famously played Aragorn.
He recalled: "I remember thinking, 'This is it. This is the end.'"
Viggo also told the story of his brush with death during a stormy sailing trip from England to his native Denmark in the 1970s.
He said: "We barely survived."
Colin Farrell and Joel Edgerton also star in 'Thirteen Lives' as rescuers John Volanthen and Dr. Richard Harris, respectively.