That cute little kid in "Jerry Maguire" taught us that the human head weighs eight pounds, but Carrie Underwood is teaching us that there are 18 inches between a human head and heart. The country superstar co-wrote Lauren Alaina's latest single, "18 Inches," with Ashley Gorley and Kelley Lovelace.

"When you're young and in love, yeah / You might do some things that don't seem all that smart / 'Cause there ain't no greater distance / Than the eighteen inches from your head to your heart," Lauren sings in the chorus of the new tune. (Watch her perform it in our studio below.) The 17-year-old "American Idol" alum says recording a song penned by her own idol was surreal.

"I look up to Carrie Underwood more than anyone, because she was on 'American Idol' and she is at the top," Lauren says. "Every artist dreams of having what she has. She's beautiful; she's a great person inside and out."

Lauren jokes that one of the highlights of her career so far has been just getting Carrie's phone number! Apparently, she has her fellow blond beauty on speed-dial.

"She gives me advice all the time, and she's got my back," Lauren gushes. "She talks about me in interviews, which is so cool! The other day, someone asked her who her favorite contestants on all the seasons of 'American Idol' were and she said me and David Cook. So ... that kinda made my life! And now a song she wrote is going to be my single, so I get to talk about her all the time. I love her!"

Lauren is seeing her name alongside a lot of big stars these days. She's on tour with Sugarland, and she just recorded with Aerosmith on a song called "Oh Yeah," which is being considered for the rockers' upcoming album, Music From Another Dimension.

Watch Lauren Perform '18 Inches' in Our Studio

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