Transcript for Billy Bush speaks out about infamous tape with Trump

It was an October surprise that rocked the campaign of Donald Trump. A lewd conversation over ten years old caught on a hot Mike. Released just weeks before the election. Then candidate trump apologized and dismissed it as locker room talk. TV host Billy bush, though, was dismissed from his job. And tonight he's speaking out in an exclusive on-camera interview with ABC's robin Roberts. Here we are seven months later. You're unemployed. Donald Trump is president of the United States. That must be a thought that has crossed your mind. I can acknowledge that the irony is glaring. It certainly has crossed my mind. Reporter: In fact, for Billy bush, his very public fall from grace nearly consumed him. The last 7 1/2 months has been a process. Sheesh, your girl's hot as In the purple. Whoa, whoa! Yes, the Donald is good! Reporter: It seemed to happen in an instant. Just over a month before the presidential leak this "Access Hollywood" tape recorded in 2005 came out. It showed now-president Donald Trump and bush having a lewd and graphic conversation. I'm automatically attracted to beautiful -- I just start kissing them, it's like a man magnet, I just kiss. When you're a star they let you do it, you can do anything. Whatever you want. Grab them by the . You can do anything. We live in a visual and digital age, so we get this video, this moment. And we react emotionally. And then you have social media and the ability to respond in realtime. And a flame becomes a bonfire very, very quickly. Reporter: Back in 2005, bush was a fresh-faced "Access Hollywood" host rubbing elbows with Hollywood's elite. He had crossed paths with reality show mega star trump several. He was at the time the biggest star on television. Not just the network with which we were both affiliated. We do want to seriously welcome our pal Billy bush -- Reporter: Last summer bush made the jump to moneying TV, his dream job as cohost of the "Today" show. But on October 7th, 2016, his career came to a screeching halt. I'm not ready for that quite yet -- Reporter: He was fired. Do you believe you should have lost your job over this? Based upon the moment that is on that tape, I understand people's reaction. I agree, I also felt that way. And I can tell you, 12 years ago, it was my first year as cohost of the show, but I was insecure. I was a pleaser. And I kind of remember wanting these celebrities to like me. So that I could keep going in this job. Reporter: One of the harshest criticisms leveled against bush was that he egged trump on. Back then, trump was about to make a cameo on a soap opera and was getting advice from Ariana Zucker. Make me a soap star. How about a little hug for the Donald? He just got off the bus. Absolutely. Melania said this was okay. How about a little hug for the bushy? The point that people drew the line is when you said, don't you want to hug the Donald, don't you have a hug for him? After hearing him say those things. Yeah. That is when people are like, oh, come on. Yes. It's one thing to agree with him and can understand that. Can you understand how people are like, no? Listen, nobody reacted harsher and more gutturally than I did. Really, really just -- killed me. I say, you know -- imagine a woman is watching that, and she thinks, is that what happens to me when I walk out of a room or out of a meeting? I'm being sized up in some way? I understand that. He was leagued on -- like egg on from the host to say dirty and bad stuff. Donald's wife Melania felt you egged him on. I definitely added to the conversation. I was keeping the ball in the air. With trump it's not much of a give and take. And I remember this moment. When he said what he said at the end. To me it was more braggadocio, his word and performance. If I had thought, I'd like to think there was a grown man sitting in front of me detailing his sexual assault strategy, I would have called the FBI. There were wrorts that you knew about the tape and you were talking about it months beforehand. I only talked about it with people who knew prior. I reported it as soon as it happened. I said, you wouldn't believe the things trump was saying off-camera. You reported that tape way back? Yeah, sure, as soon as it was done. When I was recounting what happened. I said, yeah, when the camera left, this is what the conversation was. And it was told me days later, wow, that was on. The camera was rolling. There's audio of all that. I said, oh my gosh, wow. I never thought about it again. Reporter: But the hardest part about his ordeal, bush says, was having to face his children. He is the father of three girls. My now 16-year-old daughter called me. She was in tears. And she was really upset. And she said, why were you laughing at things that he was saying on that bus? Why were you playing along with that? It wasn't funny. And there is no good answer for that. It was 12 years ago -- but it was a really bad moment. And I'm sorry. You know me, and that's not the man you know. It must be one thing, Billy, for a stranger to feel that way. But for your daughter to ask you, why? Yeah. She didn't want to hear any explanations. Just, I'm sorry. What did your wife say to you? She knows very well the man she married. And who I am. So she was supportive the whole way through. In fact, up until five minutes ago, we were on the phone before I drove up here. You're almost 34 at the time, is that really -- I mean, I understand what you're saying about wanting to prove yourself. But there are some people that said, you're old enough, you've been around enough. Your last name is bush. For sure. Reporter: His uncle is former president George H.W. Bush. George W. And Jeb are his first cousins. You have been worldly more so than most people. For sure. I should have known better, absolutely. There's no question about that. People also say you should have stopped him. But I didn't have the strength of character at the time to do that. I wish I did. Reporter: Bush says building that strength of character has taken time. And self-reflection. I'm spending my days now much more joyously, much more present. Meditation. I spend time on mindfulness. I try to daily. How do you connce some people who are going to say, you just want your job back, you just want to get back on TV? How do you convey to people that this is -- I can't, I don't think I can. And -- if they feel that way, then there's nothing I can do about it. That I am only ready to get back to work now because there is purpose and there is clarity and there is acceptance and there is a changed person. Reporter: For "Nightline," I'm robin Roberts in New York.

This transcript has been automatically generated and may not be 100% accurate.