Transcript for 'Descendants 3' stars on losing Cameron Boyce, filming franchise's final installment
Here's tj Holmes. I'm fairy godmother. Head mistress. The fairy godmother as in bippity boppity boo? Reporter: The desen daptss introduced us to the children of Disney's most iconic villains. it's good to be bad Reporter: It's a phenomenon with kids and tweens, with 21 million viewers tuning in for descendants 2. The fans were so emotional. That was something so great about the series is how much people find themselves in these films and how personal it is to them. Reporter: Four young actors playing the villain kids. Mal, the daughter of malever sent. And Evie, the daughter of the evil queen from snow white. And lots and lots of mirrors. No laughing. Wrinkles! Reporter: Carlos, who's mother is from dalmatians. I already tried. Reporter: How have your lives changed over the past five years? I have an extended family now. Reporter: Tonight the final chapter, descendants 3 is here. To the core. I think if we can leave our audience with this third film feeling that we've answered all their questions, and if we can leave them feeling closer to themselves through us, then that's success. Reporter: The empowerment themes, that you don't determine who someone is because of where they live but because of the choices they make in their life. Do the times that we're living in -- Yes. Reporter: Did they have an ininfluence on weaving the narrative that you have in the first, second and third film? Yes, and that the Disney channel stood behind them. Reporter: Sophia Carston, calls descendants the experience of a lifetime, speaking to us from a film set in Toronto. It lies in the message that true power begins and ends with love. Reporter: But for these young actors, it's bittersweet. I remember when it wasn't even the last day of filming, but we were shooting the last and I literally could not say the words. Literally couldn't say it. It was. Reporter: And the finale comes following the shocking death of one of its brightest stars, Cameron Boyce. We're family, too. We've been through a lot together. Reporter: Who or what over the past several weeks has helped you all through it? We all just have really been there for each other. The cast, everybody who knew Cameron has come even closer. And it's been a very special thing. Reporter: This is the first time Boyce's co-stars have sat down together to talk since losing their friend and colleague. And Cameron, even when he was around is the hardest person to put into words, you know? Sorry. When he walked into the room, the light changed and the energy shifted. Reporter: They still struggle to find words to describe just how special Boyce was. That's so hard, because he is such a wonderful, like, he was just Cameron. Just literally like Cameron. The person you would always ask for if you needed to talk to he was always there, and he was that person for everybody. Even when he was standing he was lit from the inside-out. If you could bottle up happiness, that was cam. He was pure happiness and pure joy. Reporter: Boyce died on July 6th from an epileptic seizure. He was just 20 years old. This is the first time I've ever dealt with something like this. And you might have said it, someone said it, just to be okay with any thought that you have. It's fine. Like, because when you're grieving, you think things. I've thought things I've never thought before. I'm 69 years long, been alive long enough to have witnessed some pretty tough stuff. This, this was as tough as it gets. I didn't realize that I had as deep a place for pain to come from. That the shock and awe of this unfathomable idea of losing this beautiful soul with such promise to this world could possibly be real. Reporter: Do you remember the last conversations you individually had with him? For me? Reporter: What were those? I mean, it was pretty normal. We all expected to see each other a lot more. Oh, we expecting to see each other a lot. A lot more. You know, because we get a lot of press coming up that we were meant to be doing, and we always do it together. Reporter: Boo boo, you remember? The last time I saw him, we were at the radio Disney awards. That was very recent, and we were just planning to hang out and make videos and we just liked creating stuff together. They were like two puppy brothers together. Yeah, he was like my little brother. There really will never be any words to describe the pain and how much we miss him. And not much helps except knowing that he lived life with more happiness than anyone I've ever known. Hey, I'm Cameron Boyce. Reporter: The premiere of descendants 3 was dedicated to Boyce. Disney aired this tribute video. It is a personal loss for so many young people who watch Disney. I truly think the best thing we can do for them is to remember Cameron exactly as he was in the most positive light. But not to avoid it. Reporter: In his memory, Boyce's family has created the Cameron Boyce foundation, to give young people creative outlets as alternatives to violence. A fitting tribute to a bright star whose life was too short but whose legacy is sure now to live on. Cameron said something. He said we all go. He said -- What you leave should be bigger than you. What you leave here has to be bigger than you. And I think it's important for us all to make every beat count, every moment count. You can watch descendants 3 on the Disney channel now.
This transcript has been automatically generated and may not be 100% accurate.