Zac Brown and Kellie PicklerZac Brown of the Zac Brown Band and Kellie Pickler had the opportunity to get to know each other during a USO tour, which included stops in Iraq, Kosovo and Afghanistan. And now that friendship could lead to something more.

"Oh, man, she's a firecracker, no doubt," Zac tells 'CMT Country Countdown USA' host Lon Helton. "We'd go to three different bases a day, helicopter in, play a show, sign 400 things, shake 400 hands, jump in a helicopter, fly to another base, play a show, shake 400 hands. It was a lot of work, but it's so rewarding being able to go places where there had never been entertainment there, ever. Kellie is a sweetheart, and I've got a song – a duet that I wrote that I think she would be perfect to sing on."

For her part, Kellie says she was impressed with Zac's devotion to his family, saying, "I just love that about people -- when you meet them and the first thing they want to tell you about is their wife. I have a great deal of respect for him. I think he's an incredible person ... very talented but most importantly, he's got a good heart. He's a good man."

Of their potential duet, Zac reveals, "She said she'd love to do it. It's just a matter of getting the timing down together to do it, but it's a smash."