One Direction Reveals New Details It's hard to imagine the music scene before One Direction, the Irish-British boy group that has rapidly taken over the top spots on the pop charts, but despite their international stardom, the fab five say they are just regular blokes trying to navigate the waves of fame. "What's happened to us in the last few years has just been mental," Niall Horan said. "Nightline" went behind the scenes -- and in their dressing room -- with Horan, Liam Payne and Harry Styles, all 19 years old, Zayn Malik, 20, and Louis Tomlinson, the oldest at 21, on Sunday as they were getting ready for the MTV Video Music Awards -- complete with funny moments, from Styles as he hits the shower and a shot of Horan's abs. In an interview with "Nightline" anchor Cynthia McFadden, One Direction talked about their upcoming third album and how dramatically their lives have changed in just a few short years. Watch "Nightline" anchor Cynthia McFadden's full interview with One Direction on "Nightline" TONIGHT at 12:35 a.m. Having sold 30 million records, performed at countless sold-out concerts, and taking home the MTV Video Music Awards on Sunday for "Song of the Summer" with "Best Song Ever," One Direction could be the first boy band worth $1 billion, according to Business Insider. VMA 2013 Winners: The Complete List Despite the fame and money, the guys said they still love to goof off with other each like they would if they were "at university together," and they haven't forgotten about their humble beginnings. It's not about being who you were. It's about keeping who you were part of who you are now," Styles said. One Direction was born out of happenstance on the British TV show "The X Factor" in 2010. When they started out, the guys said they barely had enough money in their pockets for bus fare. While on the show, each of the boys auditioned individually, and when they failed to make it into the "Boys" performance category, show creator and judge Simon Cowell suggested the five perform together. Within weeks, the group had started gaining popularity in the U.K. "We're very rare," Payne said. But we're so lucky that, you know, our personalities actually blend together so well and we're all quite easy-going. "When we sit down, we can't believe that we get on so well ourselves," Malik added. When we talk to each other, we're like, 'How crazy is it that we didn't know each other?' While they said they don't mind being called a "boy band," the five seems more like a band of brothers. "We didn't really want to follow the stereotype of the boy band," Tomlinson said. But we are, obviously, still a boy band. And we're just doing it in our own way. "We literally are the best of friends," Payne said. We hang out with each other 24/7, and we have a good time. Having international fame doesn't come without its critics, many of whom chastise the guys of One Direction for not writing their own songs and not playing instruments. The band disputes this, saying they wrote "the majority" of their own songs on their upcoming album -- out of 14 songs on the album, the guys said they wrote 10. Payne showed "Nightline" a tattoo on his forearm that said, "I figured it out" -- a sneak peek of lyrics from a song on their yet-to-be-released third album. And while only Horan currently plays guitar, others said they were in the process of learning how to play an instrument as well. "We take our music so seriously," Tomlinson said. And especially this last record ... we have done a lot of writing on it. For us, the music is such an important part. Their seemingly bizarre journey to mega-stardom is played out in the documentary, "One Direction: This Is Us," which premieres Aug. 30. Directed by Morgan Spurlock, the film follows the boys from their hometowns to landing a spot on the "X-Factor," to performing at London's O2 arena -- harkening back to the Beatles' "A Hard Day's Night," though the group said they don't see themselves as the new Beatles. "The Beatles are the Beatles," Malik said. "It's such a legacy," Payne said. I couldn't put us in the same vein as having a legacy. However, one major element they do share with the Beatles, and that the film does capture, is the throngs of thousands of screaming young female fans that not only flood One Direction's sold-out shows but also camp out outside of their hotels when the band is on tour. Several of their fans have taken to social media, expressing their love for One Direction in ways boy bands of the past never experienced before, which One Direction credits for their growing fame. Still young themselves, the group members said they found it "humbling" that many of their fans see them as role models -- something the guys seemed intimidated by. "I do think it's quite scary, being known as a role model," Payne said."We don't go around confessing to be role models or something like that. Because, you know, we might make mistakes in the long run. "We're the five idiots that they knew from three years ago, and we still are," Horan said. But the one thing that is missing from the film? Their girlfriends. "We wanted to show what the band is about," Malik said. And obviously, our girlfriends are too personal to us individually. So we didn't really want to show our individual personal lives. "We've never been a band that has lied about having girlfriends," Styles said. It wasn't a thing that we kept back on purpose. "It would have been awkward as well ... to be spending [time] with your girlfriend and just have cameras with you," Payne chimed in. Three of the five said they were "taken." Styles and Horan said they are still single. For one, being taken meant wedding bells. Malik announced last week that he was engaged to Little Mix singer Perrie Edwards, sending shockwaves around the world. Though he said he didn't have wedding details to share, Malik said he told his band mates before the news was "in the papers." In the face of constantly being in the spotlight, the guys argue they have come a long way since they made their debut three years ago. "Nobody expects us to have any control over anything that we do, but actually, it's the exact opposite," Tomlinson said. The longer that we stay in the band, the more control that we feel like we're getting over everything. So, you know, it's very important for us to be over every part of the project, really, because the brand is 'us' at the end of the day. "It's a completely different scale of life for us," Payne said. We're just normal lads trying to find our feet in such an extreme circumstance.