Watch One Direction Dish on New Album, 'Four,' at iHeartRadio Fest

One Direction iHeartRadio 2014 L
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Classic, natural, simple, crazy and upbeat. These are just a handful of words that One Direction's Zayn Malik and Louis Tomlinson use to describe the pop group's forthcoming album, Four.

"There's a good balance," Tomlinson tells Billboard backstage at the 2014 iHeartRadio Music Festival in Las Vegas. "It's definitely our most different-sounding album. We've definitely tried to keep it different, really."

1D recently announced that its next single "Steal My Girl," a preview of November's Four album, will be released in late September. But the group kept things strictly to the hits during its iHeartRadio Fest performance on Saturday (Sept. 20).

Backstage, Malik and Tomlinson dished on what fans should expect from 1D's new album. "I think it's just a progression on the last stuff we've done," Malik explains. "We haven't tried to go too different with it. We tried to keep what is our sound but just kind of grow with it, as we've obviously grown up. We've grown a bit more facial hair, and our lyrics need to get a little older as well. So we just kind of want to grow with our fan base."

See more: One Direction Wows With 'Midnight Memories' Release Party

One Direction promptly left Las Vegas to continue with its current world tour of stadiums and arenas. The group was scheduled to play the Alamodome in San Antonio on Sunday (Sept. 21), with additional dates scheduled through April 2015.

Watch Malik and Tomlinson's backstage chat below, followed by their performance.

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