TALKING to Katheryn Winnick is the perfect antidote to the eternal grey Irish winter.
She bounces into the Vikings production office in County Wicklow, Ireland, all sun-kissed hair, Colgate-ad teeth and Lagertha-like poise.
When we last left her character on the show, she was reigning supreme in Kattegatt after murdering Queen Aslaug, her late husband's wife, and claiming what she believed was "rightfully" hers. As we can probably guess, that comes at a price and one we'll see play out dramatically in season five and six.
Although she's always been portrayed as a woman in charge, a fierce shield-maiden with a heart of steely conviction, this season will test her resolve and mess with her mettle.
"It's a really interesting season because there's a lot of responsibilities to being queen," Winnick says. "There are a lot of people trying to usurp her, there's conflict with Ragnar's sons. I'm in a position of strength but I'm struggling to keep my power."
Lagertha's moral compass has always been fairly intact but in the face of such adversary, does it run the risk of becoming skewed?
It's about being a strategic ruler as opposed to one who craves war and revenge, she says. "Lagertha considers herself the queen of the people, a people's princess so to speak. She wants to do right by them, whether that's fortifying Kattegatt or growing it, she's trying to make the right decisions to move her community forward."
While she's evidently a strong characters, there are still things Lagertha fears. "I think she fears failing herself. She's had a lot of responsibility being the young wife of Ragnar, a mother and a warrior, now a queen. She's been betrayed many times and, in this season doesn't feel she can trust many people so for her not to follow her own instincts is probably her biggest fear."
For a society so at ease with violence, rape and pillage, it was oddly egalitarian and modern for its time. Women could fight alongside men, vote, divorce, own land and rule kingdoms - they had serious power.
And, thanks to writer and creator Michael Hirst, Lagertha has had a seminal role in the series, one that has allowed her character's arc to shift through many dramatic storylines. "When I landed the role I thought I'd be gone after the first season but here I am, six seasons later."
After six years, it might be difficult to find new terrain or ways of challenging yourself as an actor but Winnick confirms that Hirst never lets them get too comfortable. "Just when you feel like you've got your footing, he pulls the rug," she laughs.
This is true for season six, which sees Lagertha undergo a big physical and emotional change. "Something huge happens," she pauses, reluctant to reveal too much. But she can tell me that she makes her directorial debut in season six. "It's a huge challenge for me and I'm very excited about it, directing is a different way to contribute to the show and a chance for me to tell the story from behind the camera."
Challenge being the operative word, juggling her on-screen time with directing. "My pick-up time is 3.20am," she groans, "there's a lot of prep time to get into character so the episode I chose to direct had to be one where Lagertha has limited screen time."
There is very little Winnick can't do it seems. She brings a certain moxie and can-do attitude to her métier. When she started out she was the only woman among dozens of burly bearded men on set but as an accomplished martial artist, quickly won herself cred among her peers. Aside from her talent for roundhouse kicks and elbow punches, her aptitude for delivering emotion and drama is equally impressive, often seen in the relationship she shares with on-screen son Bjorn (Alexander Ludwig), one that she values off-screen also.
"Alex and I are very close friends. We hang out together, go for dinner, drinks. We have a strong bond, which really helps when you're acting. I've done shows in the past when I've had no rapport with co-stars and it's difficult," she says. "Living in Ireland for 10 months of the year means you become each other's family and you can see that on camera."
Does that connection pose similar challenges involving scenes that riff on animosity and violence? "I often think love and hate are the same thing in a weird way. If you have a strong emotion you can flip it but at the end of the day, we laugh, cry and then leave it on set and go for a Guinness together."
Never has Lagertha needed Bjorn more than in season five when the wrath of Ivar, Ubbe and Hvitserk gathers weight. Well, she did kill their mother. "You can't blame them really," she laughs. "But she had a hard choice, she felt she had to kill Aslaug but then she goes to the Seer who tells her that one of Ragnar's sons will kill her so there is this ongoing tension."
All the cast members have an unusual relationship with their creator in that he welcomes their feedback, allowing them some creative freedom in their character's future. Winnick is no exception.
"There's a line at the end of season four when Lagertha tells Ubbe how alike his father he is. That wasn't written in the original script but I rang Michael and told him it had to go in. Everyone can see how alike Jordan and Travis are. It's ended up being an extra layer to season five," she says.
Reading between the lines, is she suggesting a romantic tryst between Ubbe and Lagertha? "I'm not saying anything," laughs Winnick. "All I can tell you is that it's an interesting dynamic that unfolds as season five progresses."
As does the dynamic between her and Ivar who, destined to carry Ragnar's torch coupled with his thirst for blood and, lets face it, borderline madness, isn't likely to let Lagertha live peacefully. A Viking living peacefully … in the world of Michael Hirst, is there such a thing?
Vikings season five premieres on SBS tonight at 9.30pm.