Carrie Underwood has selected "Heartbeat" as the second single from her newest album, Storyteller.

Underwood debuted the new song at the 2015 American Music Awards. "Heartbeat" is a slower tune with a hint of R&B in the verses and a mandolin-tinged chorus -- and backing vocals provided by none other than Sam Hunt.

"Tonight I wanna drive so far we'll only find static on the radio / We can't see those city lights / And I love the way you look in a firefly glow," Underwood sings during the song's chorus. "Saying everything without makin' a sound / With a river rollin' the background / Underneath a harvest moon / Standin' on your shoes in my bare feet / Dancin' to the rhythm of your heartbeat."

"Heartbeat" is more soulful than some of Underwood's biggest hits. Her vocals on the new tune are still powerful and pitch-perfect, but in a more subtle way than, for example, "Something in the Water."

“I feel like a lot of the songs that I wrote and gravitated to ended up being more traditional and ‘twangy’ than anything I have ever done before. I just went with it!" Underwood says. "I love the storytelling aspect of country music … it’s one of the reasons I always wanted to be a part of it.”

She adds, "There are some things on there that are definitely familiar, but there’s a lot of growth that has happened, as well. It’s going to sound a little bit different — still the things that fans will obviously know is me. I’m not going crazy or anything, but it’s a little bit of a shift.”

"Heartbeat" is the fourth track on Storyteller, which is available now via iTunes.

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