And now, to manti te'o, the football star at the heart of that bizarre hoax, sitting down for his first on-camera interview with abc news anchor katie couric, telling what he knew, what he says he did... See More
And now, to manti te'o, the football star at the heart of that bizarre hoax, sitting down for his first on-camera interview with abc news anchor katie couric, telling what he knew, what he says he did not and how even his parents were duped by belief in a girlfriend who did not exist. Tonight, we have a special first look at her exclusive interview. Katie will be here in a moment, but with the story, matt gutman. Reporter: Manti te'o tells abc's katie couric he was duped. In love with a woman he met online four years ago, but never saw. A woman he thought died of cancer in september. He spoke of her throughout his epic football season. Even two days after the woman pretending to be his girlfriend called him to say she was alive. Was this intoxicating in a way for you, manti? I think for me the only thing I basked in was that I had an impact on people. That people turned to me and for inspiration, and I think that was the only thing I focused on. You know, my story, I felt, was a guy who, in times of hardship and in times of trial, really held strong to his faith, held strong to his family, and I felt that that was my story. Even if that hardship was perhaps exaggerated? No, it was -- what I went through was real. You know, the feelings, the pain, the sorrow, that was all real. Reporter: Behind the elaborate hoax, this man. I'm ronaiah. Reporter: Ronaiah tuiasosopo, a christian singer seen in these youtube videos -- ♪ you never let go of me ♪ Reporter: Made len nee kekua his alter ego. Tonight, with the media frenzy surrounding him, tuiasosopo isn't talking. Hey, guys? Can we talk to you? But te'o's father is talking, defending his son. People can speculate about what they think he is. I've known him 21 years of his life. And he's not a liar. He's a kid. Reporter: Matt gutman, abc news, los angeles. And abc's anchor katie couric is here right now. Such a twisted story. After you talked to him, what's the moral of this story? Reporter: Well, I think the moral of the story is that, be careful who you're communicating with online. Be skeptical. Even cynical, perhaps. I think he sincerely thought he was having a relationship with a woman named lennay kekua, online, on the phone. We saw his phone records, diane. There were multiple calls to this number, where he would stay on the phone for hours. And, so, I -- we also heard voicemails from her, that he had on his phone, that sounded very legitimate. You talked to his parents, as well, and his parents, too, were beguiled by her, had a relationship with her, they thought. Reporter: It was such an tricate web of lies. And even they were sucked in. His mom talked to her multiple times on the phone. They had sort of almost a bible study, his father would text her scripture passages and discuss them. And, so, I think they were as stunned as he was when they found out that this was all sort of a mirage. As you said, it's such a psychological maze you enter. And we're going to get to hear from him at last. We will all be catching. Thank you so much. And be sure to watch tomorrow, katie couric sitting down with manti te'o. And it airs on her show, "katie," tomorrow.
This transcript has been automatically generated and may not be 100% accurate.