Alex and Sierra performed their new ballad Little Do You Know on NBC's Today in June and now the studio version is available online.

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The song is a clear reminder why fans fell in love with the duo on season 3 of X Factor USA. The love birds sing about a difficult relationship and flawlessly croon in unison. "Just wait, I love you like I've never felt the pain," they sing.

Little Do You Know appears on their upcoming debut album, It's About Us, and fans can get a copy even before the album's release later this summer.

"You can now preorder #itsaboutus on @iTunesMusic! & you'll get a new song "little do you know" as soon as you do!" the two wrote on their official Twitter page on Monday.

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Alex Kinsey, 22, and Sierra Deaton, 23, have been promoting their upcoming album with stops at People magazine, Billboard, Teen Vogue and Vevo.

"The last couple of days have been crazy, but so much fun," Deaton said in a behind-the-scenes video from the promo tour. "We've been going from place to place just playing for people and, you know, letting people know about the album and what we've been up to, what the songs are about. It's fun to get to see what songs people respond to the most."

They released the album's first single, Scarecrow, in May, and according to Kinsey it's "a really good first look at the album." He added, "I think that it explains our personalities pretty well. It's a fun song. It's really exciting and we hope that people really gravitate toward it like we have."