back now with steven tyler's first interview since leaving "american idol." The star is back together with leading guitarist joe perry. And they talked to abc's cecilia vega about the real story and... See More
back now with steven tyler's first interview since leaving "american idol." The star is back together with leading guitarist joe perry. And they talked to abc's cecilia vega about the real story and "american idol." ♪ Reporter: There's only one way to describe aerosmith's performance at this weekend's ihart music best in las vegas. They rocked the house. ♪ Living and going down ♪ Reporter: Even backstage away from the lights and screaming fans, aerosmith is 100% rock 'n' roll. And steven tyler is 100% steven tyler. This is butch cassidy and his brother is the sundance kid. Reporter: They may beside by side now, but it has been a bruising year for this legendary man. The two presentmen made head lions for the decision to be a judge on "american idol." You're going to hollywood. reporters he did not want aerosmith's name involved with the show. And now with tyler, they're back and awaiting the release of a new album in november. This is the best record we've ever made. This year. When we put it together, it was like, what if we write a song for what they're going to listen to in the shuttles 20 years from now going to mars. What would they want to hear? Reporter: Teel early and perry are rarely interviewed together. They've had a rocky relationship for decades. There's one topic that continues to be a sore subject. It was the biggest show on tv. Every night, millions of people got to see that big -- sing, being what he is. It didn't hurt aerosmith. They were a little jealous in the beginning that I took it. I didn't tell them I did. Well, speak for yourself. I wasn't jealous. You were the first to go to the press. No, I was upset because I had to read about it in the press. That's what I just said. I wasn't jealous you were on the show. I was glad you were on the show. Reporter: If tensions lingered inside the band, fans didn't see it this past weekend when they performed with a superstar lineup, including rihanna, no doubt and so many more. I'm so stoked to see everybody. You got an electronic house. You got rock. Country. Everything. This is the type of event that you want to be associated with. Reporter: Those who really know aerosmith like the festival's developer said the band is better than it's ever been. What do you see this time around? How unified they are. Excited about music. I think this album is one of their best ever. Reporter: After more than 40 years together, it seems they have come full ci. We're going where no band has ever gone before. We've thrown together the ideas. Tom hamilton has two songs. Joey's got a song. And it's unbelievable. And how about that. ♪ Don't want to close my eyes ♪ Reporter: The band is just getting warmed up. For "good morning america," cecilia vega, abc news, las vegas.
This transcript has been automatically generated and may not be 100% accurate.