"There's an old soul living inside him. That's what we think."

That's how Tammy Miller explains the otherwise inexplicable talent of her 10-year-old son, L.D. Miller, whose jaw-dropping virtuosity on the harmonica has been the brightest spot in Giddy Up, the country-themed production show that finishes its three-month run April 2 at the Tropicana.

It's not so much that L.D. has such impressive technical ability, but that he infuses his bluesy, two-song turn with the kind of depth one would normally expect from someone five or six times older than he.

That's why his mother believes reincarnation is the only plausible answer. But while the origin of such raw emotion remains a mystery, it's easy to understand where his instrumental prowess comes from.

"All the music comes from (L.D.'s dad) Larry," says Tammy. "He and his group, The Miller Brothers, played in the Pentecostal Church." Today, dad, like L.D., performs with the family blues band named for one of L.D.'s two older brothers, Clayton. Brother Cole rounds out the group, which is based in Lafayette, Ind.

L.D. took up the harmonica at age 5. "I wanted to do something different (from the other family members)," he says. "My dad brought me into a music store and I saw a harmonica in a glass case. I said, `I want one of those, Dad.' " It proved to be a wise choice. L.D. was a natural on the instrument, which led to formal lessons a year later. The program was a bit too technical for the 6-year-old, but his teacher knew that wouldn't be a problem. "He said, `I wouldn't mess with it, whatever he's doing, he's doing a good job,' " recalls Tammy.

About the same time, L.D. made his debut with The Clayton Miller Blues Band, a big draw on the college and festival circuits. The Tropicana booking marks his first engagement away from the family business. If it's been a tough adjustment for him to make, L.D. is hiding it well.

"It's been fun meeting all the people (in the show) that are so nice. And all the glamour, and seeing all that's going on in the casino," he says.

But being a child prodigy has given home-schooled L.D. the chance to do more than spend this winter in Atlantic City. He's also been on Steve Harvey's Big Time, the WB network's talent show. That led to a surprise, on-camera visit from L.D.'s hero Stevie Wonder, a former harmonica-playing prodigy in his own right.

"It blew my mind. It was crazy," he says. "I was teaching Steve Harvey something, and I saw the crowd stand up. I looked to my left, and Stevie Wonder was coming in. At that moment, I couldn't breathe."

And during a meeting last year with producers of The Tonight Show, L.D. wound up playing harmonica for Ringo Starr while the rock legend and some of his band members provided rhythm on various pieces of dressing room furniture.

Starr's opinion? "That's a hell of a lotta blues for a 9-year-old," L.D. remembers him saying.

When he's home, L.D. is much like any other 10-year-old. He enjoys racing remote-controlled model cars, riding his dirt bike and swimming. But unlike most kids his age, L.D. pretty much has already plotted out his future. "I'd love to be touring and playing to millions of people," he says. "And living the rock star life."