Wee ones in the audience of “Mary Poppins” (playing at the Kennedy Center through Aug. 22) probably assume it’s “magic” when Gavin Lee — as peppy chimney sweep Bert — tap dances up one wall, across the ceiling and then down the other wall during the song “Step in Time.” But it’s also balance, body awareness and an assault on gravity.

Since Lee originated the part on Broadway, he’s been doing the trick for six years and is now fairly comfortable hanging around 35 feet in the air. “The fact that the blood rushes to my head for 30 seconds every night probably clears my head,” he says.

And although getting the feel for tapping horizontally and upside down took getting used to, it’s not that taxing. “At first, when I had to hold there, I’d be shaking, and I was sure I was going to have the best six-pack in the world,” he says. But with technological improvements, he doesn’t need abs of steel to stay steady.

Lee does, however, need something to keep his stamina up for the entire show. He used to drink 5-Hour Energy, and he’s now switched to a big cup of Starbucks. With enough caffeine, he could probably tap on the ceiling without any magic at all.

Photo courtesy Disney/CML