Traditionally, celebrities don’t start rolling into Indianapolis until Memorial Day weekend.

This May, they didn’t wait that long.

When Saturday’s IndyCar Grand Prix began, Indianapolis Colts quarterback Andrew Luck gave the starting command, former Colts star Robert Mathis was driving the pace car, actress Alicia Silverstone was waving the green flag and former television show host David Letterman was on pit lane.

The speedway just seemed like the place to be.

“I am a race fan, now,” Mathis said. “I have a great amount of respect for the drivers, the pit crews _ just everyone associated with it because it really is something special."

Mathis, who retired after last season, has been a regular at the track the last four years.

Luck’s appearance was no surprise, either, given that he’s spent much of the offseason in town rehabbing from shoulder surgery. Plus, he arrrived at the Brickyard on his preferred mode of transportation _ a bike.

But the addition of Letterman, an IndyCar team co-owner who usually arrives for the Indianapolis 500, and Friday night’s red carpet screening of “Diary of a Wimpy Kid: The Long Haul” certainly gave Indy’s first open weekend of the month a Hollywood feel.

“In the film, Greg reroutes our (family trip) to Indianapolis, so that was kind of the connection,” Silverstone said, explaining she screamed while taking laps in a two-seat car driven by Mario Andretti at speeds approaching 150 mph. “It was so great to see it with the audience, and the fans were howling at all the right bits. At one point, a dad behind me was yelling ‘that’s us, that’s us.’ It was great to see.”

And, apparently, it was great to be seen in Indy in mid-May, too.