MINNIE Driver is at home at the "little place" in north Malibu she shares with her toddler son Henry and getting ready to go for her daily surf. "It's going to be a classic Monday," says the actress, and you can hear the smile in her voice.
• Driver as a pensive Frances Kelly in The Deep.
Her sunny Californian life is a long way from Glasgow, where she filmed new BBC1 thriller The Deep in the depths of winter. "It was minus 11. I had a little temperature gauge at work and there were days when I'd come in and just want to throw up, knowing that we'd be out there all day. It was definitely hardcore," says the 40-year-old, who was last on our screens in US import The Riches with Eddie Izzard.
Driver explains that in The Deep she and co-stars James Nesbitt and Goran Visnjic are part of a team of scientists on a mission to find a source of renewable energy in the depths of the Arctic Ocean.
The previous team all died in their submarine amid strange circumstances, so the crew of Orpheus, led by Minnie as captain Frances Kelly, are slightly nervous about what they might find. Not to mention the hazards of the deep, including crushing water pressure and boiling gases.
Driver says she was drawn to the character of Frances, as well as the quality of writing. "She reminded me so much of Ripley in Alien, and the whole thing was like the Abyss and State Of Play, action films and political thrillers. It ticked all the boxes for me and it would really have to, because it would take a lot to get me to bring my little boy to insanely freezing Glasgow in the winter!"
The shoot ran from December to February but, luckily for Driver, it didn't involve diving in an actual sub. "No!" she squeals. "I'm with Laurence Olivier. You know, there's that famous story when he was shooting Marathon Man, and Dustin Hoffman would run for 26 miles before they'd shoot so that he would be in the right place and Olivier went, 'You should try acting, dear boy!' I'm with Larry!"
But she did watch a documentary by James Cameron, Aliens Of The Deep, in preparation. "It's all about scientists discovering organisms that survive on chemosynthesis as opposed to photosynthesis and a lot of very interesting stuff that I had no idea about. It was very educational, preparing for this role."
Does Driver believe there might be things under the sea we haven't yet found?
"Without a shadow of a doubt," she says. "If you have organisms that are not just living, but thriving, with billions of them living off gases coming out of these deep volcanoes, then yes. It's really exciting because it does offer up the potential for an alternative energy source. The series poses a lot of really interesting questions, apart from being entertaining, I hope."
It certainly is entertaining – gripping even. The first episode introduces us to all the characters and we soon learn that Frances and her married colleague Samson (Visnjic) have slept together, while Clem (Nesbitt) is mourning his wife, who died in the previous mission. As captain, Frances has to make some tough decisions when the mission starts to fall apart.
"She's slowly compromised by what is going on and it's interesting getting into the psychology of a person who has to make these life and death decisions. How do you make that real and human when you have no experience of it?
"If you keep it real emotionally, you understand why people make the decisions they do, even if they're ones that make you go, 'Oh God! I would never do that'."
The series threw up another challenge for Driver – working with computer-generated imagery for the first time.
"It was absolutely hilarious, I'd like to see some of the outtakes!" she says, laughing. "There were moments where you're looking at hot-pink gaffer tape taped to the top of a metal pole and one of the guys was walking along with it saying, 'OK that is the underwater volcano and the yellow one is a massive iceberg'. You're meant to be looking at a 900ft icecap under the ocean'."
When the cameras stopped rolling, single mum Driver spent all her free time with baby Henry, while the cast and crew sampled Glasgow's finest restaurants without her. Driver did manage one night out on the town, though, and recalls: "You've never seen anything like James Nesbitt and Goran Visnjic taking down a pub in Glasgow!"
For the most part, the actress, who has always kept the identity of her one-year-old child a secret, says that her son kept her busy. "We went to the science museum and a lot of music classes, so I did all kids' stuff. Henry's incredible, he's so adaptable, he makes it very easy. But it was a lot more stressful (with a baby].
"I would love to have been able to decompress after a really emotional day's work, and just go to a restaurant and sleep late on a Saturday morning, but it's a very different thing when you have a child."
After small roles on TV, London-born Driver's breakthrough came in 1995's Circle Of Friends, followed by Good Will Hunting, alongside Matt Damon, which earned her an Oscar nomination. Since then her career has progressed in fits and starts, with roles in Will & Grace, The Phantom Of The Opera film and last year's Motherhood with Uma Thurman, which made just 88 in its opening weekend here. She says she was "horrified" when The Riches was cancelled after just two seasons, despite Emmy and Golden Globe Award nominations for Driver.
"I've officially never been as devastated by the loss of a job and the ending of something as I was over that, because it was an unmitigated success. I was nominated for every major award in the US and I just didn't understand it, it left such a bitter taste in my mouth, because it was so good."
Now 40, she says she hasn't noticed any age discrimination in Hollywood so far. "It's always challenging being a woman in this industry, but it's as good a time as it's ever been since the heyday of Bette Davis and Joan Crawford. Maybe not in the great big Hollywood blockbuster schlocky comedies where they want a 22-year-old acting opposite a 38-year-old man, maybe not there, but that's OK, they can keep those movies," she laughs.
She's just made films with Dustin Hoffman and Hilary Swank, and she's proud of her 17-year career. "My criteria's always been the same – you do the very best thing that comes your way and I can stand by pretty much every single thing I've done, bar maybe a couple."
But she's even more proud of her baby bundle of joy, Henry. "He is the greatest thing I ever did and there's just so much joy and so much laughing. I feel terrible when I work sometimes that I don't get to spend … you know, that's hard, because I'm a single parent and obviously I don't want to be away from him, but I've got to work."
Motherhood means Driver picks her work carefully these days. She's just turned down a film in Canada in winter, admitting: "I don't have it in me", and she's due to make a film in Wales, which will be closer to the grandparents.
"I'd really like Henry to go to school in England when he's bigger," she says. "But it's idyllic here. I love barbecues and the beach and hiking and horseriding and I like wearing shorts and T-shirts and flip-flops. I love England, but living here affords me the lifestyle that I want to give Henry." So no plans for another series of The Deep in freezing Glasgow? "They'd have to shoot it in Hawaii for me to do it again!" she laughs.
• The Deep is on BBC1 on Tuesday August 3 at 9pm