The two say dancing will help their driving in the Rolex 24 at Daytona, Fla.
Credit: John Raoux; Brian Cleary/Grand American Road Racing/AP

Patrick Dempsey and Dancing with the Stars champ Helio Castroneves usually get other people’s engines running – but now the two TV hunks are revving up on their own.

The handsome pair delivered their star power to Florida’s Daytona International Speedway on Saturday for the test sessions preceding the first major auto race of the year, the Rolex 24 at Daytona, a 24-hour endurance race that will pit Dempsey, Castroneves and scores of other drivers against one another Jan. 26-27.

But Dempsey – who has been moving up the motor-sports ranks with some top finishes in 2007 – and two-time Indianapolis 500 winner Castroneves might just have a leg up on the competition – literally. Both say that dancing has helped their driving in surprising ways.

“You’re on your feet all the time, and it certainly helps your conditioning and cardio and legs,” the Grey’s Anatomy star, 41, who also waltzed in the movie Enchanted, told PEOPLE. “It’s a great workout. But it probably didn’t help me quite as much as it helps him.”

Suggests Dempsey with a laugh about Castroneves, “He won’t be climbing fences anymore [when he wins races]. He’ll be doing dance routines!”

“My legs are really strong now,” Brazil-born Castroneves, 32, dressed in a red driver’s suit, told PEOPLE before getting into his racecar. “Normally, as drivers, we work the upper body, neck, shoulder, arms, but dancing was mostly the feet and the legs, and wow, it was a big change. I’m feeling great. I’m not sore. It made me fit and lean and – wow!”

In addition to executing his fancy footwork to prepare for the race, Dempsey says that his New Year’s resolution is to train harder – by cycling. “Last time I was on the bike, it was 40 miles, so I’m trying to up it to 50 a day,” he says. “I’ve found that makes the biggest difference for me in the car. I have better stamina and certainly in terms of braking and things like that.”