The former NASCAR star was signing autographs at a dirt track in Jackson, Minnesota, over the weekend when he ran toward a heckler and socked him right in the face, as shown in video posted on social media.

Stewart was driving in a sprint car race at the Jackson Motorplex when his engine blew after the first lap, according to TMZ. He then signed autographs for fans, but one fan reportedly was furious at Stewart and accused him of bailing from the race on purpose.

“F–k you, Tony,” the fan said, according to TMZ. “You piece of s–t. You come here and basically race for one lap and quit, you piece of s–t.”

Stewart reportedly responded by saying, “I blew my engine, you f–king a–hole. Do you want to pay for it?”

WARNING: VIDEO CONTAINS NSFW LANGUAGE

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