Tim McGraw's latest album, 'Sundown Heaven Town,' has already spawned three hit singles, but it's the record's next single, 'Diamond Rings and Old Barstools,' that McGraw is perhaps most excited about. A family member joins him on the song -- but it's not his wife, Faith Hill.

"My cousin, Catherine Dunn, is on the record," McGraw tells Billboard. "She's my mom's baby sister's daughter, and she's a great singer and songwriter."

After testing the boundaries of radio with some of his previous singles, including the recent 'Lookin' for That Girl,' the singer says 'Diamond Rings and Old Barstools' is perfect for the airwaves.

"It's a classic, great country song," McGraw says. "When you come across those kind of songs ... these songs kind of allow you to dig in, and they have a little bit of country nostalgia, but also a modern edge. When I run across a song like that, I can't wait to get into the studio and record it."

McGraw says he has learned to be extremely picky when choosing songs to include on his albums.

“For me, the perfect combination -- and what you strive to find as an artist -- are those songs that have both [the lyrics and the music] involved,” he explains. “It’s lyrically spot-on perfect, and the melody is something that just sings itself practically."

McGraw will be hitting the road this summer for his 2015 Shotgun Rider Tour. He is also set to headline the 2015 Taste of Country Music Festival, taking place June 12-14 at Hunter Mountain, N.Y.

Download 'Diamond Rings and Old Barstools' here.

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