BADBOY NASCAR champ Tony Stewart was caught on camera grabbing the der­riere of fellow driver Kevin Harvick’s wife – and the offensive hand-to-bumper squeeze is now en­raging Harvick.

In full view of TV cameras, free-wheeling Tony – notorious for his explosive temper and unpredict­able antics – sneaked up behind DeLana before a Sept. 16 race at Chicagoland Speedway and “tail-gated” the beauty.

Tony’ longtime friends Kevin and DeLana appeared to laugh off his cheeky on-air grope, but Tony has repeatedly done it through the years, and sources say Kevin is finally get­ting fed up. Off camera, he exploded after discussing the groping with his wife and finding out how badly it humiliates her, the sources add.

“Everyone got a good laugh the first few times Tony sneaked up behind DeLana and unexpectedly pinched her on the backside, but now the joke has gotten old and Kevin wants it to stop,” an insider told The ENQUIRER.

“He’s fit to be tied. Behind the scenes he’s ranting and saying things like ‘that SOB is treating my wife like a sex object in front of millions of fans. It’s disrespectful to her, to me and to our marriage. He’s crossed the line.’ Kevin even furiously told Stewart: ‘Don’t touch my wife.’

“Kevin finds it demeaning to DeLa­na and personally humiliating to him that Tony would continue doing something so embar­rassing to his wife, especially when he knows there’s a good chance it would be caught on camera and broadcast around the world.”

Tony, 41, and Kevin, 36, have been close friends since Tony drove for the Harvicks’ team years ago. The three-time Sprint Cup Series champion claims pinch­ing DeLana’s butt is a pre-race ritual he does for good luck.

“I drove for them for a long time, and I have a great friendship with them,” Tony ex­plained. “It’s always been good luck for us. You got to do what works.”

But sources predict that Tony’s luck is going to run out if he crosses Kevin much longer.

“It’s not just the butt-grabbing that has Kevin reaching his boiling point,” said the insider. “It’s Tony’s general lack of respect for other people’s space.

“He doesn’t think twice about sneaking up behind Kevin and scaring him when he’s working under the hood of his race car, or barging into the Harvicks’ mo­tor home late at night without even knocking.

“Kevin has had a bellyful of Tony’s bullish in-your-face antics, and it’s only a matter of time before these two go head-to-head.

“If Tony doesn’t back off, he’d better start watching his own butt!”