Nearly 350 people who braved the heat Sunday morning for a grueling triathlon got a surprise when some famous race car drivers showed up.

NASCAR drivers Jimmie Johnson and Kasey Kahne flew up from Daytona, where they raced Saturday night, to start the triathlon bright and early at James Island County Park.

“It’s almost unbelievable that somebody would work their schedule to do a 400-mile nighttime race in Daytona, get on a jet plane and come to Charleston and then start a race that begins at 7:15 in the morning,” Charleston Sprint Triathlon Series organizer Paul King said.

The third of the five-race series was the hottest yet, with the mercury already at 80 degrees by 8 a.m. and climbing rapidly. It didn’t seem to bother Johnson and Kahne, who both looked fresh when it was all over.

About 350 spectators came out to cheer participants on.

Kahne sent out several Tweets after the event, including this one: “The happiest I’ve ever been to see a finish line while running in the back. Haha. First Sprint Triathlon in Charleston! Good times.”

He finished with a time of 1:11:30, which put him in 44th place out of 346 competitors.

Johnson posted a photo of himself being interviewed by television reporters on his Twitter page Sunday morning, with the message: “Even the media came out. I finished in 1:11:57. I cramped on the run and missed my goal by 2 mins.”

He finished in 46th place. This was the first triathlon for both men, and King was thrilled they chose Charleston for their debut.

“They said if there’s a way they can do this again, they will,” King said.

Kahne said he hoped to be back on his Twitter feed Sunday: “Thanks to @JimmieJohnson for getting us all pumped up for our first sprint tri. Really enjoyed it. Looking forward to more down the road.”

The drivers drew a crowd after the race and posed for scores of photos. Johnson, 36, is married, while Kahne, 32, is famously single.

“They’re charismatic as all get out, in a very humble way, which makes them almost more charismatic,” King said. “They’re totally accessible and very gracious, just very nice guys.”

Reach Dave Munday at 937-5553