here? It's getting steamy on "the heat index." One of the hottest boy bands ever, one direction, are establishing something even the beatles did not. cynthia McFadden talked about the movie, music and... See More
here? It's getting steamy on "the heat index." One of the hottest boy bands ever, one direction, are establishing something even the beatles did not. cynthia McFadden talked about the movie, music and she found a way to get into their love lives. Of course I did. I was told I wasn't suppose to. They won a vma for best song of the summer. What's it like to sing in front of thousands of screaming girls? Well, we talked about that. As well as whether or not they were going to have a few surprises about their new music. Take a look. ♪ Get out get out of my head ♪ Reporter: They're young. Energetic. ♪ Crazy, crazy, crazy till we see the sun ♪ Reporter: And hot in every since of the world. No one is more sizzling right now than one direction. ♪ Let me kiss you ♪ Reporter: And right now, only where legions of screaming girls have dreamed of going, in their dressing room. Reporter: Come back. I'm going to get into the shower. Reporter: It looks like these guys are having fun. They really are, as their brand-new documentary shows. Although, all that fun makes interviewing the five of them a challenge. We're going to sing all of our answers to this interview. ♪ Amazing ♪ Reporter: You can sing for me if you want to. The movie is a look at life on the road for the megastars. If there's a theme, what is it? Fun. Mischief. Reporter: Not many human beings are going to have the experience the five of you have had, in front of that many screaming girls, right? What is the -- try to tell me what it feels like. We describe it, you could be in the worst mood. Having the worst day. And the minute that scream goes up to start a show, and you hear that roar, you can't help but not smile. ♪ Crazy, crazy, crazy ♪ Reporter: One thing the movie does not show, is any sign of the band's girlfriends. We have never been a band that lied about having girlfriends. People have been going out with, we have. So, you know, it wasn't like a thing that we kept back on purpose. It wasn't because it's bad for business? No. No. Lying looks bad for business. Reporter: Who is available now? And who is available? Available? I'm available. Reporter: Zane is the one member of the group definitely off the market. Just days ago, he got engaged to girlfriend, perry edwards. tell me when you're going to get married? I'm not sure myself. So, I don't know. ♪ I let the little things slip ♪ Reporter: As it turns out, all the young stars feel the same way, busy. Especially as they're taking control of their own music. One of the criticisms of the band is that most of you aren't playing instruments. And that you're not writing much of your music. Not true. Not true. We actually wrote maybe I'd say -- 10%. It depends. 13, 14 songs on the next album. We wrote the majority of them. Reporter: And music? There are some mehdis. Reporter: Ten years from now, will the band be around? Well -- I think we just -- we love it. And you know, we've been having a lot of fun. And working really hard. I think we want to keep doing that. Well, here are a couple of little nuggets for their fans out there. One of the new songs has the lyric, I figured it out. And all the boys, except naill, has a cross tattoo on their ankles to keep them grounded. The film opens up across the country. I don't want to be a jerk, but i have to say, I loved it. I loved it. I'm not the demographic. But all you moms out there, it was fun.
This transcript has been automatically generated and may not be 100% accurate.