Donnie Wahlberg Recalls Bruce Willis' Support Ahead of 'The Sixth Sense's 25th Anniversary (Exclusive)

The comments came ahead of 'The Sixth Sense's 25th anniversary.

Donnie Wahlberg is sharing what it was like to work with Bruce Willis. In an interview with ET's Nischelle Turner, the 53-year-old actor gushes over his experience starring alongside Willis in The Sixth Sense ahead of the film's 25th anniversary later this year.

"In my time working with him, Bruce was so cool to me," Wahlberg tells ET of Willis, who's currently battling frontotemporal dementia. "... Bruce was so supportive... He just had my back... It was a great thrill to work with him and to get to know him."

Wahlberg's big moment in the film came when his character, Vincent Grey, died by a self-inflicted gunshot wound in front of Willis' Malcolm Crowe, his former psychologist.

"Even the scene that we did together, it's one scene, but I was watching him and as out of my mind as I was on that day, I was like, 'He's so technical. He hits his mark and then he goes to the emotion,'" Wahlberg says. "He was just so helpful and supportive."

As helpful as Willis was during the project, the actor's greatest attribute really shined at the film's premiere.

"I remember when we went to the premiere of The Sixth Sense he just kept hugging me and saying, 'You did so good. You did so good. You really helped the movie,'" Wahlberg recalls. "But afterward, when we talked he was like, 'What do you think? You think this movie is gonna do well?' I loved the script, so I was like, 'This is gonna be the biggest movie ever.' And he was like, 'Really? You think so?' He was so humble and curious and not assuming anything and not presumptuous."

For Wahlberg, a young actor on the rise at the time, that example meant a lot.

"[It] was a really big moment in my career, to be across from him. He had my back and... he was so supportive and so grateful for the effort that I put in it," he says. "... I left that movie... with an incredible sense of confidence. If he hadn't supported me, I don't know that I would have had that confidence. I don't know that I would be here right now. That's how impactful it was... It meant the world to me and then to see how humble he was through all of it was just very impressive. I try to approach my career that way to this day."

While Willis made the experience on set a good one for him, there were challenges Wahlberg faced in his role.

"I spent five weeks suffering and starving myself and doing all this stuff. It was really hard and it probably took me a year or two to get back to my right mind. Not that I was dangerous or anything, but what I went through to change physically, starving myself, I think I had a little bit of an eating disorder for the next two years," he says. "I thought about every time I ate. I was like, 'Oh, I can only eat this much,' and I would like run to the gym after having a regular meal. I just kind of wasn't myself. I really went through such a transformation for that part that it was really difficult for me to come back."

Given that experience, Wahlberg is happy not to go through a dramatic physical transformation for a role again, instead preferring to stick to playing Detective Danny Reagan on Blue Bloods, which recently got renewed for a 14th season.

"I'm just incredibly grateful. It's very unbelievable to be doing so many things that I love to do," Wahlberg tells ET. "... I've been doing this show for 13 years. I'm so grateful for it. I have a great cast who became family. We have a great crew and so many loyal viewers and fans... Growing up I dreamed of somehow making my way to be able to do things that I love to do and to be doing it after all these years and having so much fun doing it, I just feel so blessed and so grateful."

Another thing Wahlberg is grateful for is his true crime series, Very Scary People. Wahlberg hosts the series, which chronicles the dark and twisted lives of an array of diabolical criminals.

"Forensic Files was my show for years... I think, because of Blue Bloods... it created this opportunity for me to do this," he says. "But in reality, on Very Scary People my job isn't so much to investigate or do any of that, it's really to just present... the information and then let the people close to the story, the people who were involved, the families and all those people, tell the story, because they know it better than anybody."

As for why people have such a fascination with true crime, Wahlberg speculates that it's "because we don't understand."

"We think we can understand what would make someone do something, [but] we have no idea. I think we're afraid in a lot of ways of what's out there and what could harm us. In some ways, I think watching it, and maybe trying to get a better understanding of it, can inform us of better ways to sort of watch our backs and protect ourselves and give us a little insight to help us understand and maybe make us a little less afraid."

Very Scary People's new season premieres April 16 on ID Discovery. Tune in to Tuesday's episode of Entertainment Tonight for more of ET's interview with Wahlberg.