Gary LeVox of Rascal Flatts may be a country superstar, but when it comes to his daughters, he's just like any other doting dad. And as of late, ol' dad has become a little concerned that his girls are growing up too fast ...

One of LeVox's daughters in particular, nearly-14-year-old Britney, is starting to act like a teenager ... and seems to have developed eyes for the sexy Luke Bryan. “On the bus she’s like, ‘Oh my gosh, Daddy look, Luke Bryan, look how tight his shirt is’, and she’s 13, you know," the singer says.

Bryan does have that effect on females (especially when he's strutting his stuff onstage) -- even Flatts bandmate Joe Don Rooney's wife. "My wife said the same thing today, though," he chimes in.

Adds LeVox jokingly, “Yeah, it’s kinda weird. They both got a belt and they’re in time out.”

Thankfully, Britney and 10-year-old Brooklyn LeVox still look up to their father as an artist, too. “We’re still cool and relevant at my house, which is good," he reveals.

The 'Payback' hitmakers are currently on the road for their Rewind Tour, but unfortunately for Britney, Bryan isn't along for the haul. However, Sheryl Crow and and Gloriana are special guests on this road run, and even though they don't shake their hips like Bryan, they're pretty cool, too.

See Luke Bryan Shirtless!