A medic was called on set to assess if The Ballad of Wallis Island star Carey Mulligan and the cast were not getting too cold while they filmed the movie in coastal Wales during the summer, the director has said.
Watch: The trailer for The Ballad of Wallis Island
In the upcoming comedy-drama, Mulligan - who is married to singer Marcus Mumford - plays one half of a disbanded folk duo opposite Plebs star Tom Basden as her ex-boyfriend.
The movie, which has had critical acclaim in the US, sees a fan - portrayed by comedian Tim Key - pay for them to reunite and perform a gig on an island, called Wallis.
At the gala screening at the Ham Yard Hotel, London, on Wednesday, director James Griffiths told the PA news agency: "Tom especially was going blue through most of the takes.
"I think there was a medic going in, and you too, right [Carey]? We had a medic sort of checking your temperature for the cold stuff. It was freezing."
When asked if it was filmed during the summer, Oscar-nominated actress Mulligan said: "It's Wales."
Basden, who co-wrote the film with Key, said the rural location, believed to be in and around Pembrokeshire, was "beautiful and it was unpredictable, weather-wise, and it was challenging".
Key said: "We shot the short film [version] 18 years ago, and we're kind of very eager to get back to Wales. Feels like it's a big part of the film. Weirdly."
Mulligan also recalled that the filming over a few weeks felt like a "summer camp together".
London-born Mulligan, whose mother is originally from Llandeilo, Wales, also said: "I had such a little baby when we were filming, it's just attached to all these, like, gorgeous memories of my baby being little.
"And you guys were all around, and everyone was cuddling her, and we were all sort of together for a bit. So it's very precious to me."
The original short film, The One and Only Herb McGwyer Plays Wallis Island, was nominated for a 2008 BAFTA short film prize, and saw Key and Basden in the main roles and Griffiths directing.
Mulligan has been nominated three times for the Best Actress Oscar, for the coming-of-age hit An Education, revenge thriller Promising Young Woman, and the biopic Maestro.
In April 2012, Mulligan married Mumford - lead singer of Mumford & Sons - and the couple now have three children.
She has previously appeared on soundtracks released for movies she has starred in, including Maestro, Inside Llewyn Davis, about a fictional folk singer, and the period drama Far from the Madding Crowd.
The Ballad of Wallis Island opens in cinemas on Friday.
Source: Press Association
