‘Game of Thrones’: Jaime Lannister is driven by love, but for how much longer?

When it comes to family life, Jaime Lannister of “Game of Thrones” and his real-life alter ego, Nikolaj Coster-Waldau, couldn’t have less in common. When we call at his home in Denmark to chat about the HBO series’ fifth season, Coster-Waldau is in the middle of making dinner for his daughters, while the sounds of piano practice occasionally fill the background.

House Lannister, meanwhile, is the most vulnerable it’s ever been in the show’s four seasons. Its patriarch, Tywin Lannister, was murdered by his own son, Tyrion.

“Tywin was a ruthless man, but Jaime — even though he found him very hard work — he was his dad, and he never in a million years imagined that Tyrion would kill him,” says Coster-Waldau. “So there is grief in the beginning, but also Tyrion’s actions have put them all in a pretty difficult spot.”

Without their father, and armies from two sides of Westeros setting their sights on King’s Landing, will desperate times call for desperate measures? And what about his on-again, off-again relationship with his sister, Cersei? Coster-Waldau sets the scene.

Jamie is a good man — how does he square that with loving Cersei, who’s often cruel to others and even him?

As he said to Brienne: “You don’t get to choose whom you love.” And he has a long history with Cersei; he knows her, and he knows what she’s been going through. But for me, sometimes I go, “How long can he keep this up?” Does anyone really believe that it’s set in stone, that once you’ve decided to love someone, you’re going to have to keep doing it? Because he hasn’t been getting a lot the other way.

But he’s a very loyal man to the people he loves; he says, very very early on in the show, “The things I do for love.” Sometimes, he doesn’t get it himself. He claims to understand it, but he knows that he just has to do whatever he can for those people. That’s also why he helped Tyrion escape, and obviously it had some very unfortunate consequences, but he acts out of good heart.

What’s driving him forward now? What does he want to accomplish?

He lives in a world where, because it’s who he is and what he’s known for, he says it to Tyrion last season, “As soon as they find out that I can’t fight, I’m done.” It’s almost like a boxing champion, everywhere they go they have to have bodyguards around them because people want to fight them, they want to prove themselves. And in a way it’s the same thing with Jaime Lannister, he’s the Kingslayer, and up until now everyone feared him, and he always had that in the back of his head: “No matter what, I can fight my way out of this situation.”

Now he can’t do that anymore, so he has to train, he has to see if he can get any better with his left hand —it’s just a question of survival. And this season, he needs it;there’s a couple of interesting things that happen —the training might come in handy.

What can we look forward to?

We’re in the home stretch now; everything’s been put into play. We know all the main characters really well, and now it’s time for them to start meeting up in a way. The endgame is coming. This season is changing the dynamic of the show, and when we get to episode 10, it will have significantly changed in quite a few ways.

Are you preparing to film Season 6 now?

That depends whether I survive this season.

The show is getting away from the books. How do you feel about not knowing what will happen?

It’s great, and it’s also sometimes frustrating. Actors are different; some actors love the unknown, but I loved the first three seasons, when I knew exactly what was going to happen. Having said that, with Jaime this season it’s all off book, so it was so exciting to get those scriptsand see what the guys came up with, because it was really cool.

I’ve heardthe hardest part of filming can be keeping a straight face.

Without giving anything away, Tywin died and there’s a scene where he’s lying in state, and knowing Charles Dance, who is a joker and has extremely dry, British wit, it was very difficult to stand just looking at him. Even though he didn’t do anything, but you kind of just you knew that he would – it was very difficult for me and Lena [Headey] to get through that scene.

Who will win the Game of Thrones?

They should just abolish the monarchy because it doesn’t do them any favors. Let’s get a democracy in there. ButI would pick Bran Stark,I think he has potential.

“Game of Thrones” premieres Sunday, April 12, at 9 p.m. on HBO.