As anticipation grows for Kings Of Leon's "Come Around Sundown" -- the follow-up to the Tennessee rock outfit's massively successful "Only By The Night" album -- the band is gradually letting fans in on details of the new record. 

A music video teaser for first single "Radioactive" -- which hits radio Sept. 13 -- was released on Kings of Leon's YouTube account, and it features lead singer Caleb Followill playing guitar inside a sunlit barn with a children's choir. 

Although "Radioactive" might be new to the public, bassist Jared Followill says the band has been kicking the song around for a while. "We played it forever. We started playing it around the time right after we wrote [2005's] 'Aha Shake Heartbreak.' It was kind of in between 'Aha Shake Heartbreak' and 'Because of the Times,' and there was actually a few songs like that that didn't make it. You know, we save songs until we get them right."

Judging from the video, the band appears to be aiming for an even more expansive sound with "Radioactive," using the children's choir for the song's background vocals. "We went into the studio and we tried it and it wasn't really working, so we were going to scrap the whole song. But then Caleb went back to this old spiritual song that we all sang growing up," Jared said.

Drummer Nathan Followill joked, "After my Grandma sees this video, she definitely won't think we're going to hell as fast as she did think we were going." 

In addition to the video teaser, Kings of Leon also revealed the tracklist for "Come Around Sundown," due Oct. 19. Here is the tracklist: 

"The End"

"Radioactive"

"Pyro"

"Mary"

"The Face"

"The Immortals"

"Back Down South"

"Beach Side"

"No Money"

"Pony Up"

"Birthday"

"Mi Amigo"

"Pickup Truck"