Following in the footsteps of David Coulthard, fellow F1 veteran Jarno Trulli has become the next grand prix star to stop in at a NASCAR event.

The Toyota driver's first stop on Sunday, after entering the Michigan International Speedway almost unrecognised, was to visit his former formula one rivals Juan Pablo Montoya and Scott Speed.

"They were the first two people I visited with," Trulli, 33, is quoted as saying by Detroit Free Press.

"They were surprised to see me," the Italian, who last weekend contested the Canadian grand prix, added.

He refused to rule out switching to the popular American stock car categories at some point in the future, even though he admitted that Sunday was his first trackside visit.

"Maybe one day -- a test or something," Trulli said. "It's all sound and feeling. Everything is exciting and unexpected."

"It's all so different from formula one," Associated Press also quoted him as saying.

He said he respects NASCAR drivers.

"It's not so easy as people think," he insisted. "Juan is having a bit of a hard time. The racing is very tough."

Trulli also enjoyed the anonymity of his Michigan experience, after normally attracting a lot of attention at motor races.

"A few people asked me for autographs when I first arrived but it basically cooled down," he said.

"In Italy or France, you would basically be surrounded."

Source: GMM