When 24 ended in 2010 after a grueling eight seasons, Kiefer Sutherland happily segued to the FOX series Touch and several movies, including the recent Pompeii. But dammit, a character as iconic as Jack Bauer was just too good to quit. Start the clock—Sutherland returns for a dozen new London-set episodes under the title 24: Live Another Day (Mondays on FOX, 8/7c).

Tonight’s premiere finds our hero, a wanted fugitive who’s been off the grid for four years, emerging from hiding to stop a terrorist threat against the visiting U.S. President (William Devane). But first he has to rescue his tech-wiz wing woman Chloe (Mary Ann Rajskub) and elude a couple of CIA agents (Benjamin Bratt and Yvonne Strahovski). Oh, and deal with former flame Audrey Raines Boudreau (Kim Raver), the President’s now-married daughter. We asked the seasoned star about all things Bauer.

“The great dynamic of this character, and what he’s had to suffer, is having to make those terrible choices where you allow 10 people to be sacrificed to save 100. I’ve always respected that aspect.”

What has it been like to come back to Jack after four years away?
Honestly, I’m a little nervous going back but very excited about the opportunity. I was very proud of those eight years, and the audience has been so spectacular and supportive and loyal, to not give them the best that we’ve got to offer would be very disappointing. I was fortunate enough to go off and do things that I really cared about, like Melancholia and The Reluctant Fundamentalist.  But I’ve never done anything that had a kind of explosive reaction by an audience, that sustained over that long a period of time like 24. Unlike films where you make them in a vacuum, audiences were watching 24 while we were making it; you just get a sense of it on the street, what people are liking and what they’re not liking. It was a very collaborative experience. So the opportunity to do it again is very exciting and very special—and now very nerve-wracking.

What makes him so captivating?
Jack Bauer is a character that has an unbelievably strong moral center. Everything that he has done has been about trying to accomplish a mission and that mission is always to save people. In the end the great dynamic of this character, and what he’s had to suffer, is having to make those terrible choices where you allow 10 people to be sacrificed to save 100. I’ve always respected that aspect of the character and that’s what I like about him.

What’s Jack’s frame of mind as the series begins?
He’s very motivated. He has a very specific agenda. He’s very much been operating on his own so he does not have the same kind of loyalty that he had before, certainly with regards to Chloe. He’s had enough things happen to him that he doesn’t trust anybody. He was always a hard guy but I think he’s even harder now. Chloe and Jack have had a relationship over the entire span of the show and they have been allies. At the very beginning of this show, they’re actually pitted against each other by virtue of a set of circumstances. It’s also something that’s going to evolve over the course of the show.

“I’m sure we’ll be hated by a large portion of London for snarling up their traffic, and for that I apologize in advance.”

What does setting these episodes in London bring to the table?
London has some landmarks that are unbelievably significant and it will be very exciting to shoot with the Tower of London in the background. I think it’s a huge opportunity from a storytelling point of view and broadens the scope of the show. I was born in London and spent huge parts of my life there. It’s a place where I feel very comfortable.  But I’m anxious about shooting outside, blowing things up. I’m sure we’ll be hated by a large portion of London for snarling up their traffic, and for that I apologize in advance.

It’s a physically demanding action role. How did you prepare?
I started training last summer. I do a run every day. Lighter weights, heavy repetitions, everything I can for endurance because it’s a grinding show and I’m not getting any younger. As you get older, there are certainly different things you need to do. I probably run a lot more now than I did back then. I probably used more weights back then. Everything is designed for endurance and being able to run all day. I’m in the best I’ve been in my life.

There was talk of a 24 feature film a few years ago. Did that morph into this series?
No, this is a very different script, and it presented itself to us first. If it ends up causing a film to be made, so be it, but right now we’re focused on this.

You have Forsaken coming up with your father, Donald. What was that experience like?
Fantastic—it was the first time. We’ve never worked together. It’s a western, about a gunfighter who accidentally kills a child in a gunfight and decides it’s time for him to go home. And when he gets home he finds out that his mother has passed and he is now stuck in a house with a father that he is very estranged from. The night before we started, I called him and said, ‘I hope you have a great sleep, I’ll see you in the morning,’ and there was a long beat and I said, ‘And just so you know, I’m really nervous.’ And he went, ‘Oh my God, thank God, me too!’ So we had a laugh and got that out of the way.

No matter what else you do, you’re forever linked with 24 and Jack Bauer. Are you OK with that?
Yeah. It’s something I’ll be associated with for the rest of my life, and I’m very proud of that.