Jack Bauer was back at Comic-Con International in San Diego for the first time since 2009, as 24 star Kiefer Sutherland and executive producer Jon Cassar opened the first day of programming with a panel devoted to Fox's recent “limited event” series 24: Live Another Day.

Famously set in real time, with each episode of a season representing an hour in a single day, 24 wrapped its initial eight-season run with Sutherland’s terrorist-busting hero deemed a terrorist himself by the United States government in the 2009 series finale. He was last seen walking off into the sunset, going into hiding underground. 24: Live Another Day picked up years later in London, as Bauer comes out of hiding to stop a terrorist attack against U.S. President (William Devane), who's speaking there.

The panel opened with perhaps one of the most memorable sizzle reels in Comic-Con history: a “Jack Bauer’s greatest moments” compilation. The loud, high-octane video was full of so many “badass” Bauer moments that the audience’s enthusiasm and energy was high when Sutherland appeared on stage.

Asked by Cassar to speak about his experiences shooting 24: Live Another Day in London, Sutherland said one of the big differences was the crowds that would show up to watch.

“In Los Angeles, police could tell people ‘You can’t walk there.’ In London, they can’t. People are very clear about their rights. ‘This sidewalk is mine. I paid for it. This isn’t the Magna Carta.’ In some of the scenes we would get up to 3,000 people watching,” he said. “Now the amazing thing about that was that the 3,000 people actually listened. We would tell them ‘All right, our cameras are pointing this way now, would you mind moving across the street?’ and you’d see this giant ant farm of people moving across the street. I would start laughing because we would never be able to do that back home.”

“We would put a barrier up and tell them to move behind the barrier and they did,” Cassar added. “In Los Angeles, they would steal the barrier.”

Sutherland continued, “There was a very emotional scene where Mary Lynn Rajskub, who plays Chloe O’Brian, was telling me that her son and husband were killed, and we’re in a car, and what nobody knows is that literally five feet in front of us there were 2,000 people in a park watching us do that scene. Mary Lynn was like, ‘I don’t know how to do this,’ and I said internalize it, and she did it, and it was fantastic, and she started to cry. I said, ‘Wow, that came out of nowhere,’ and she said ‘No, I started crying because I can’t believe 2,000 people were sitting there watching me in the car, and I didn’t know what to do.’”

Cassar asked Sutherland what went through his head when he got the call saying they were interested in bringing back 24.

“We left it open at the end of Season 8 because we had every intention of doing a feature film, and for a variety of reasons that never ended up happening,” Sutherland replied. “The character of Jack Bauer has been the biggest blessing of my life and when I got the call from Howard Gordon saying he had this great idea, what do I think about doing it again, there were about five minutes of ‘Oh, I could never ...’ Then it was, ‘When do we start?’”

Sutherland said the main concern was that they had done eight solid seasons, and he didn’t want to tarnish the legacy of the show. “We all re-signed pretty quickly, though.”

The actor also noted that the current Bauer is different from the Bauer of Season 1. “I went back and watched the very first episode. There was so much hope in this guy," he said. "He was even smiling in the episode. He was in the kitchen with his wife. The evolution of this guy is that he’s lost so much, and with everything he’s lost, he’s run out of patience. There’s nothing in his immediate future that he’s fighting for, so it’s a different character.”

Cassar asked about the final scene of Live Another Day, in which Jack surrendered himself to the Russians in exchange for Chloe, who was being held hostage. The Russians have been after Bauer since Season 8, when he  infiltrated the Russian embassy and killed several diplomats. In the scene, Bauer walks to the helicopter where the Russians are, turns to Chloe, smiles and gets in. The helicopter takes off, and the assumption is that Bauer will be tortured and imprisoned.

“Well, he managed to save Chloe, and it gave him some satisfaction. The day was over,” Sutherland said. “We went through so many different ideas for that ending. Even Jon and I were like, ‘Maybe for the DVD we’ll have Jack pull out a hand grenade in the helicopter and blow it up.’ We’ve never had that kind of freedom before, where the end was whatever we make it. On some level, we kind of copped out because it’s hard to let it go.”

He talked about how different the television landscape is since he began acting in the early ‘80s. “Television used to be the end of your career,” he said, noting how TV characters back then never changed. But shows like The Sopranos and ER changed how characters can be portrayed over the long term. “The Tony Soprano at the beginning of The Sopranos is vastly different from the Tony Soprano in the final season. They are two different men.”

“Acting on television has been one of the most rewarding acting experiences of my life,” he continued. “I’m a huge movie fan, but I find myself going to less and less films. When I look at Ray Donovan or Boardwalk Empire or Game of Thrones, there’s just so much great stuff out there. It’s been an honor to be a part of that transition.”

Speaking of Game of Thrones, actress Michelle Fairley (Catelyn Stark) played one of this season's big villains, Margot Al-Harazi. When Bauer finally met up with Al-Harazi on screen, he threw her out a window to her death. Cassar mentioned how originally, Bauer was supposed to come inside the window and shoot her, but they came up with throwing her out the window on the day of filming.

Sutherland said that, on the day of shooting, “I looked at Jon and said, ‘I don’t get it. I don’t get a scene with her? I at least want to be able to say that I’ve worked with her.’ So we did a few lines. We struggled a little. She’s the strongest short person I’ve ever met. So by the time I throw her out the window, I was quite happy,” he said, crediting the U.K. stunt crew for helping to make that scene work so well.

The scene where Bauer breaks Benjamin Bratt’s hand was also improvised. Sutherland says that over the years the seeds that made Bauer a badass just grew and grew. “Someone on the set would casually say, ‘We should pull the car over and set that guy on fire,’ and the actor would say ‘Yeah, do it! Do it!’ The seeds grew. Organically," he said. "That’s the best way I can explain my experience on 24 -- people came in and they wanted to do something different or be bold, and it kind of shaped how we did the show."

Cassar asked how much of Sutherland is in Jack Bauer and how much of Jack Bauer is in Sutherland. “Oh, we’re vastly different. Just look at my record,” the actor smiled, referring to his history of DUIs, which even led to a short jail stint midway through the series. “The difference is that I have a sense of right and wrong, and I try to do what’s right, but don’t always succeed. Jack has a sense of right and wrong and he lives by it. That moral compass is his way of life. I promise you when I grow up, he’s the guy I hope to be.”

24: Live Another Day will be available on Blu-ray/DVD on Sept. 30 from 20th Century Fox Home Entertainment.