Transcript for 'American Idol' returns to TV on ABC: A look back at show's legacy
It's the show that made Simon Cowell a household name. Along with Carrie Underwood, Kelly Clarkson. Yep, "American idol." It changed the face of music and reality television, and now it's back. Promising to be bigger and better than ever before. Can they pull it off? And this is "American idol"! Here we go! Reporter: After 15 seasons on another network, last year's swan song for "American idol" included a cryptic sign-off at the finale from host Ryan Seacrest. Good night, America. For now. Reporter: Did he know something we didn't? Drumroll. Reporter: Because it was just today -- Announcement! Week reveal right here ABC is bringing "American idol" back. Reporter: That's right. Our tears had only just begun to dry. It wasn't a good-bye, it was kind of a so long, farewell, see you soon. I have not missed it. But I will watch it again. Reporter: Immediately Hollywood's abuzz with potential judges. And who might host? Kelly Ripa prodding Ryan Seacrest about a possible repeat performance. Typically I really only save prayers for world peace and people who are very sick and stuff like that. But I am- I'm going to start a prayer circle. Because I was like your original fan. I would love to see a woman in the position. And love to see a mom who is also a comedian. That can also carry a ??? tune ??? Reporter: "American idol" was a show stopper and a game changer, the highest-rated show on television for eight consecutive seasons. More than 36 million viewers at its peak, it gave contestants a truly national launching pad. People watched because you never knew if that next contestant might just take off. Was like this giant Cinderella story. Everybody knew Kelly Clarkson had been a waitress, then she was a superstar. The winner is -- Kelly Clarkson. Reporter: Clarkson was an unknown singer from Texas when she won season one of "American idol." ??? Moments like this ??? Reporter: Millions of albums and three grammys later, she's a bona fide star. With hits like "Stronger." And "Since you've been gone." ??? I can't breathe ??? From the start I thought Kelly Clarkson was a great singer. She's a very strong person. And that really came through in the career that she's had ever since. Reporter: And who doesn't love Carrie Underwood? Taking a smoke break. ??? Sometimes I need a smoke break ??? Reporter: But mostly belting out powerhouse anthems like "Before he cheats." ??? Before he cheats ??? Reporter: 12 years ago she was just another contestant on season 4. ??? Because I can't make you love me ??? Going to L.A. For "American idol" is so scary. I was crying like in the car on the way to the airport. Because not only was I flying for the first time, I was flying by myself. Reporter: Carrie Underwood went on to sell more than 64 million records. And win seven grammys. To say a that this show was a juggernaut is almost an understatement. The one show that has given us stars that you don't think of them as "American idol" winners, you think of them as stars in their own right. Reporter: Even leasers could end up dream girls like Jennifer Hudson, sent home early despite being widely praised by the judges. But it all worked out. ??? Jennifer Hudson. Reporter: That performance won her an Oscar. It wasn't just the contestants. The chemistry between original hosts Paula Abdul, Randy Jackson, and Simon Cowell, part of the reason for the show's success. I would just like to see Simon, Paula and Randy come back. I really think that will be the key to getting people excited to watching it again. Because we miss that original magic. Reporter: Simon's signature snark showing the truth sometimes hurts. I think you're amazing. Really? Amazingly dreadful. Will he be softer now he's a dad? Will Paula be as whack a do? Will Randy still have weird glasses on? Reporter: The trio moved on, replaced by a revolving door of celebrities. Among them Ellen DeGeneres. Steven Tyler. J. Lo. And of course Nicki Minaj who futted with cojudge Mariah Carey. Nobody said every moment -- Excuse me -- That the music will cut me off -- Clean your ears out -- This is "American idol." Reporter: The one constant, perennial host Ryan Seacrest. I was terrified. I put on a bit of a brave face the first couple of episodes. I wasn't quite sure how to run a live television show. Reporter: In 15 seasons, there were plenty of unforgettable performances. ??? Talk to me tell me ??? Reporter: Remember William hung? No one's going to replace "She bang." Reporter: If imitation is the greatest form of flattery, idol must have felt flattered paving the way for shows like America's got talent, X factor, and the voice. ??? despite that, the pioneering show suffering dwindling viewership. And finally giving its then final bow. By the end of "American idol's" reign, they weren't turning out stars like Kelly Clarkson and Carrie Underwood. But you never know. If this show comes back and people have the appetite for it, if they're people that viewers connect to and there's somebody on there with talent that brings something that we haven't seen before, I think that absolutely another superstar could come out of the show. Reporter: A moment like that could make this gamble pay off.
This transcript has been automatically generated and may not be 100% accurate.