Emily Watson (entre) as Helen Wilton in Everest with Elizabeth Debicki as Dr. Caroline Mackenzie and Sam Worthington as Guy Cotter.
The widow of mountaineer Rob Hall has spoken of her support for the film which dramatises the last days of his life and death on the world's highest peak.
Dr Jan Arnold attended the Venice Film Festival world premiere of Everest with her daughter Sarah Arnold-Hall with whom she was pregnant when her mountain guide husband perished in the 1996 Himalayan tragedy.
Dr Arnold, portrayed by Keira Knightley, was wary of a film being made. But after seeing the approach by British production house Working Title, which is headed by New Zealand-born producer Tim Bevan, her concerns were allayed.
"One of the reasons I felt okay with it was because it's Working Title and their approach was more akin to how I thought it could be well told.
"I didn't want anything over-dramatised, over Hollywood-ed. They had made United 93, the story of the fourth of the 911 planes, and that was really well done."
The film depicts Mr Hall's death after he and his climbing party were stranded by a storm but he was able to say goodbye to his wife in Christchurch via a radio-phone link.
"I've always been able to visualise Rob on the south summit, the highest person in the world alive on land at that time.
"That ability to talk with him patched down with the radio by satellite phone in those days was actually quite a thing, but it was extraordinary to be able to communicate to somebody who you know they're going to die, and I did know that - we always said you might as well be on the moon and they did use that line.
"If you're on the south summit or higher and you collapse, unless there are people right there with you, your chances of survival are slim. So I think it kind of helped me. After you stop shivering you just drift off into a sort of hypothermic, hypoxic low-oxygen sleep.
Also at Venice was Helen Wilton, who was Mr Hall's base camp manager, played by Emily Watson.
"This film has been through many hands since 1996 and at the beginning it was easy to say no. There was too much happening for us. It was too private, too painful."
She too was convinced after a trip to New Zealand to discuss the film with Bevan, director Baltasar Kormakur, and actor Jason Clarke who plays Mr Hall.
"It became obvious they had already researched - a good start as there are many myths around and we were very wary. Ultimately we felt respected and I still feel they've been true to their word."
Dr Arnold said she understood why some involved in the tragedy - including the Sherpas - got little time in the drama.
"It was a slight casualty of needing to compress and condense and just tell a few stories well. In a way tokenism would be worse. It would need to be a fully developed character and there are many other characters who are also missing."
The Venice opening night was the first time Clarke and co-star Jake Gyllenhaal, who plays American climber Scott Fischer, had seen the completed film. Other members of Mr Hall's extended family also attended.
"It was overwhelming," Clarke admits. "Jan was there with a lot of the Hall clan who'd come from everywhere to see the film, which says a lot about the Halls and New Zealanders."
Gyllenhaal said, "Watching the movie I realised how no matter how hard we try in cinema, it's no match for reality.
"The most powerful image of the film is really Sarah at the end and seeing the connection and the beauty of that scene between Keira and Jason; observing the love Rob and Jan had right till that last moment was so moving."
• Everest is released in New Zealand on September 17.