The last time I interviewed Sofie Grabol, which was also the first time, was in the autumn of 2012, soon after the final series of The Killing had finished production and she had already begun shooting an independent Danish movie, The Hour of the Lynx, in which she swapped Sarah Lund's weirdly famous sweater for a priest's dog collar. Lund mania was still at fever pitch, but Grabol herself was busy shaking off the character that had made her a star. We spoke then near her home in Copenhagen and although she was perfectly friendly and attentive, she also seemed drained. "Yes, I remember," she says now. "That was just before I became ill."
Grabol spent the following 12 months being treated for breast cancer, and now, after spending most of 2014 in London (playing Margaret of Denmark in The James Plays at the National Theatre and filming Fortitude, a big new drama for Sky Atlantic), she seems far happier and - yes - more alive. "I'm fine now... I hope I'm fine," she says. "You wish you could say 'over and done with' but it is kind of a shadow that is there. The fragility of life is something you have to live with.
"But this year has been amazing for me. It's been so intense working in London... it's been like a marathon. I always felt a bit puzzled by why people who've had cancer always seem to be doing Iron Man things and climbing mountains and doing marathons; I was always, 'What is that?'. Then it suddenly hit me: this is what I'm doing this year. This has been my marathon or mountain climb."
Did she come to any conclusions about why people feel the need to challenge themselves following a life-threatening illness like cancer? "Actually, I've been thinking about this a lot and, this sounds odd, but there is this almost shame connected to getting ill," she says. "I think it's almost an animalistic feeling that you're weak, and maybe somewhere deep down I'm trying to prove to the rest of the flock... is that the word?... that I'm still valuable."
Grabol's own marathon began just three weeks after the last operation for her cancer, when she was flown to the remote east of Iceland to begin filming her role in Fortitude. Set on an island off the Arctic coast of Norway, hitherto the preserve of mining companies and scientific researchers, Grabol plays the local mayor who is, controversially, hoping to encourage tourism. "In this place things can come at you from nowhere... monsters," says someone near the start of Simon Donald's 12-part drama - and the frozen milieu brings to mind both Fargo and the polar denouement of Mary Shelley's Frankenstein, while at the same time being entirely its own thing. A large, mainly British cast also includes Stanley Tucci, Michael Gambon, Christopher Eccleston, Johnny Harris, Jessica Raine and Richard Dormer.
"There are more than 25 main characters," says Grabol. "We were just dumped in Iceland in a hotel in a small village out in the middle of nowhere, and for me that was the most... violent... violent is the wrong word. The thing is that I was scared, actually - scared just to start working again. Just how do you work, how do you act? Starting again without one single person that you could, like, feel familiar with was very, very frightening."
But also, she thinks in retrospect, therapeutic. "It corresponded with my inner landscape somehow, because I felt that everything in me was rearranged, and then to be put into an equally new outer landscape with an unknown group of people... There was something very nice about being an explorer on all levels."
The cast bonded quickly over shared meals, long walks on days off, and Michael Gambon's apparently hilarious story-telling. Grabol admits to being star-struck when meeting Gambon. "I remember seeing The Singing Detective when I was a teenager, it made a huge impact on everyone in Denmark," she says. "It made me think this is what acting can do. It's not like I formulated I wanted to be an actor or anything, it's just that, you know, the revelation of his performance."
By now, hopefully it's clear that Grabol is not only a deep thinker - in the manner that BBC4 viewers fondly assume that all Danes are - but that she can articulate these thoughts in English better than many English people. "It's interesting that whole language thing," she says. "I don't know what happens in your brain when you speak a foreign language, but it feels like it is a different part of your brain. So for me, this year has been almost like I've had two parallel lives. Whenever I have three days off, I fly home to my kids and, obviously, we speak Danish and stand in the kitchen cooking dinner and sometimes I go, 'I can't be on stage in three days doing that play in English... I don't think I can do it'."
Grabol's mother, an architect with a fascination with Chairman Mao and all things Chinese (Grabol and her brother could handle chopsticks from an early age), separated from her biological father before her birth in 1968 - and Grabol learned English from her American stepfather, who in turn separated from her mother when she was 11. At which stage the family joined a commune. "I did not want to go and I actually threatened to kill myself," she says. "However, I didn't get my way and it was a brilliant thing. There were lots of teenagers like me, and we might actually be made for that [communal living] and not be made for sitting in our little units."
It was her mother who suggested the teenage Grabol audition for her first part, opposite Donald Sutherland and Max von Sydow in a biopic of French artist Paul Gauguin - a role she won despite never having studied drama. She's been acting ever since, gaining a reputation for romantic comedy - before The Killing came along and changed her life.
"I straighten my back when people talk about The Killing because I'm proud of it," she says.
Will Grabol ever slip back into Sarah Lund's sweater, a trophy currently residing at the back of her wardrobe? "You can never say never... that's what I've learnt these last years. Who knows what will happen in life?"
For now, she's just looking forward to spending more time with her two children - 13-year-old Bror ("it means brother in Danish") and 10-year-old Gudrun.
Grabol seems re-energised, a sunnier and more tactile person than I met two years earlier in Copenhagen. However, she is careful to stress that what happened to her body was not in any way a blessing. "It's not like I'm a different person, in no hallelujah way or any other ways," Grabol says.
"It's not like I've seen any light, which I think some people expect, especially with cancer which has so many myths attached to it; it makes me sick really. There are so many ideas about that illness, and one of them is that you have to be almost considering it as a gift, but I would definitely be without this experience."