'I Played Tommy in Titanic. Leo and Kate Were One of Us'

I was 24 when I got the part of Tommy Ryan in Titanic. As a proud Irishman, it meant a lot for me to play a character who was representing the hope of Irish people moving to another country. He's a good character, funny and sweet, so it was nice to portray a character like that who was looking for a better life for himself.

Today is the 25th anniversary of the film, and it feels like a lifetime ago that I auditioned for James Cameron and got the role.

I knew straight off the bat that it was going to be a very big film, since Cameron was directing it. And then when I went to Mexico, where we filmed for six months, I realized how off-the-scale it was, compared to anything I'd ever done.

Filming in Mexico

I'd never been anywhere other than England and Ireland, and I was flown First Class to Mexico. I didn't have a clue what perks came from flying First Class; I didn't know I could order whatever I wanted. I felt completely out of my depth in that kind of world.

The first time I arrived on the studio lot, I remember going over this hill and seeing the ship in the distance. Because of its lights, and the fact we were in a desert, it looked like a spaceship. But as you got closer, you saw it was the Titanic.

We did a lot of scenes on the ship. I think it was probably one of the last movies where they built the set. If they were to do it now, it would probably be all green screen. But it was real, and it was ginormous; it felt like you were on the real ship.

My first day on set, Kate Winslet and Leonardo DiCaprio were doing their thing on the raft where she lets him go. I came over when they were done and said hello and Kate said, "I saw your audition tape. I thought you were very good, so it's great that you got the job." And I said, "That's sweet of you."

I started filming a couple of days later; there were no readthroughs or rehearsals, it was just straight into it. I was young so it didn't make any difference to me. I had no fear. I guess I had that young, slightly naïve, taking-on-the-world attitude. As you get older, that slowly gets chipped away from you.

Memorable moments behind the scenes

All the actors were staying in one hotel, including Leo, although Billy Zane and Kate Winslet had their own accommodation outside of the hotel.

The hotel used to have a free bar every evening from 7 p.m. till 9 p.m., which was dangerous. The actors were there for five or six months but a lot of them wouldn't work for weeks on end. They weren't sent home in that time because we never knew who Cameron might want in the background of a shot at any given time.

I was lucky that I would always work at least a day a week, so I was always engaged. But I remember a party where Cameron was talking to one actor and asked, "What are you doing here?" And the man said he had been cast in a particular scene, where a rescue ship was supposed to come and help. And Cameron said, "Oh, that scene's gone." They had cut the scene, and I think they sent the actor home soon after. In fairness, he had a lovely, three-week paid holiday in Mexico for absolutely no reason.

My most memorable moment on set, in terms of acting, was when my character is stuck behind the railings and he's screaming and trying to get out. I did a bit of improv with that. I loved the energy of that because I really felt that I was representing the working class trying to get out of there. Even though my character was fictional, we were going through actual stuff that must have happened, that must have been so heartbreaking.

The filming itself was incredibly mechanical in parts. They built four sets, half-underground and half-overground, that they could tilt any time they wanted. So Cameron would go, "Give me an extra two feet," and you would feel the ground underneath you tilt, and the water would come in. Cameron's a creative guy; he's always pushing the envelope.

I'm a writer and director now, so I wish I had stood behind James Cameron and watched how he was doing things. I'm not saying I was young and dumb. There was probably a naivety to me, and I really enjoyed the experience, but I should have learned more from it. Older Jason is looking back and going, "Younger Jason, I just want to slap you in the face. Soak it up more!" But when you're 24 years of age on a huge movie set, what are you going to do?

Forming friendships with co-stars

Both Leo and Kate felt like one of us at the time. I'd seen both of their work, and knew who they were, but they were both down-to-earth. Kate is very funny, and Leo is hilarious. I loved working with him. He was such a goofball—all of a sudden, he would just start dancing in his green room, and it was like, "What the hell?" He would crack a lot of jokes, too.

Leo had a little posse of friends with him while we were filming. Looking back now, I know Tobey Maguire was one of them, but I wouldn't have known who he was at the time. He had David Blaine, too. I remember him doing magic tricks and thinking, "This guy is crazy."

Leo kept with his gang of guys, but not to the extent that he was never with everyone else. He would sometimes have drinks in the hotel with us, and we'd often go into the little town on weeknights, when it was free of tourists, and have drinks. My memory of Leo is of him being a good guy, very funny and very open. I got the impression that he really appreciated the opportunity he had, and he treated the people around him very well.

Leo and I were good mates on the film, and we exchanged phone calls for a little bit afterwards. I didn't have a mobile phone, so I would call his landline in the U.S. when I was back in London. But after the premiere, we kind of lost contact. I think he changed his number and I wasn't able to get hold of the new number. I'm sure he was the kind of guy who would be changing his number every few weeks because as soon as people got hold of it, they'd be calling and calling him.

Even if I had his number now, I'm not the kind of guy who would call after 25 years and go, "Hey, how's it going?" But I think if I bumped into him, we'd have a laugh.

I got on well with Billy Zane during filming, too, and we are still in touch. Kate and I shared multiple scenes together, and I remember us having dinner at her house on location. We exchanged emails for a little bit but when you don't live in the same country as somebody, it's a bit tricky to keep a relationship going.

After the cameras stopped rolling

We finished filming in March, but the film was supposed to come out July 4, which was never going to happen. Paramount and Fox were freaking out because it was always summer movies that made the money, so they were terrified of releasing it in December. There was a race against time; Cameron was editing during his lunch and on weekends, and doing 18-hour days. He wasn't getting any sleep. I don't know how he managed it.

When I was back in London, I read the trade papers that said the film was a disaster, it cost too much money, and it was going to be a flop. But I didn't think it would be. I thought people would go for it.

And then I saw it at the premiere. I was struck by the enormity of the event. There were paparazzi everywhere and loads of late-90s celebs. In the theater, I was two of three rows back and Leo came in with Prince Charles. He looked at me as if to say, "What the hell is going on here?"

As soon as we saw the film, I knew it was going to do really well. It ticks so many boxes: you've got the love story, the sadness within it, the fascination of the Titanic and the special effects. It's got everything.

It got an incredible reaction: I saw people cry and it got a standing ovation. And then we all marched out into Leicester Square for the after-party. I had never been at an event like that before in my life. They must have spent a fortune as it looked incredibly lavish. It was huge, with different sections that got more VIP as it went along. Because I was in the film, I was in the VIP section. Leo was there, and I remember a lot of girls liking him a lot.

When the film opened, it stayed at number one for months. It was trippy being part of that. I was getting recognized by people on the street, which I'd never had before. And going back to Ireland was kind of crazy because the Irish audience resonated with my character a lot.

The attention died down, as time went by. But even today, because of social media, I still have people getting in touch, drawing pictures of the character and sending them to me. It's really sweet. I'm grateful that Tommy resonated with people. And now there's a whole other generation of people who are watching Titanic. I think it's the kind of film that's going to stay around forever.

Jason Barry is an actor, writer and director based in L.A.

As told to Newsweek's My Turn deputy editor, Katie Russell.

All views expressed in this article are the author's own.