Petty, a seven-time Cup Series champion, and Andretti, who has competed in the Indy 500 nine times, unveiled the "Petty Blue" and "Day-Glo Red" paint-schemed car at Indianapolis Motor Speedway.

"This is pretty exciting news for all of us," Petty said. "Never did I think I would have the opportunity to be part of the Indianapolis 500. I know how much this means to John Andretti and the Andretti family, and I'm looking forward to seeing John on the track in May. I'm not sure if I can be of any help to him, but he's going to have no bigger supporter than myself."

Petty will enter the car in a partnership with the Indianapolis-based team Dreyer & Reinbold Racing. Window World will sponsor the team's efforts.

Richard Petty Motorsports fields four cars in the Sprint Cup Series. His team - formerly known as Petty Enterprises - merged with Gillett Evernham Motorsports at the beginning of the year.

Andretti drove for Petty's team from 1998 through the middle of 2003. He won his second and most recent career Cup race in 1999 at Martinsville, which also was the last time a Petty car has been into Victory Lane. Andretti became the first driver to compete in the Indy 500 and the Coca-Cola 600 on the same day in 1994.

"It is great to drive the 43 car again for Richard," Andretti said. "We have had success before in the stock cars, and we hope to have another strong run in the Indy 500. This year will mark my 10th Indy 500, and, with support of Window World and Dreyer & Reinbold Racing, I am really excited about being a part of Richard's first entry into open-wheel racing."

Andretti, the nephew of 1969 Indy 500 winner Mario Andretti, has competed in the first seven Cup races this year, driving the No.34 Front Row Motorsports Chevrolet.