The Kiernans used the car avidly for years, adding more than 30,000 miles to its odometer. But, as with many vehicular toys, mechanical and family issues eventually intervened. “The clutch went out in ’80 and I was born in ’81,” said Sean Kiernan, Robert’s son, who grew up with the McQueen Mustang in his family’s garage. “So it kind of went into storage.”

The Kiernans have kept the car a secret, mainly to ward off rumormongers and gawkers. But that didn’t stop Steve McQueen from finding them in 1977. “Dad had owned the car for three years at that point. And he got a phone call from Steve asking about the car, how it was, if he’d changed anything on it. And McQueen said, ‘I would really like to buy it if there’s not too much involved with it. I’ll replace it with a similar, like kind of car. As long it’s not a crazy amount of money,’” Kiernan said. “But dad declined. He said, ‘Thanks, but no thanks.’”

McQueen didn’t take no for an answer. “I think a week later, a letter to my dad arrived from McQueen and it had the Solar [McQueen’s production company] letterhead and stamp on it. And it said, basically, ‘I’d love to talk to you again about purchasing my car back, if not too much money is involved. Otherwise we’d better forget it.’ And dad never reached out, he did forget it. And that was kind of the end of that.”

This was a decent decision. The car is now valued at $3 million to $5 million.

Left, Kiernan with his 1968 Mustang and the new 2018 Ford Mustang Bullitt edition, painted the same color; Right, Steve McQueen with Molly’s mother, Terry McQueen. Left, courtesy of Ford; Right, courtesy of Molly McQueen.

Robert Kiernan died in 2014 without ever having driven the car again. As a means of honoring his legacy, Sean decided to use the film’s 50th anniversary this year as an incentive to get it roadworthy again. Fortunately for preservationists, he has maintained the car’s originality and patina, simply repairing the mechanical systems. The car will be inducted into the Historic Vehicle Association roster this year—kind of like the National Register of Historic Places, but for cars. It’s only the 21st car to be so honored.

Since it sat, unworking, for his entire life, having the opportunity to get behind the wheel now is a very strange experience for Kiernan. “I’d never seen my dad drive the car,” he said. “The only person that I’d seen drive the car was Steve McQueen, in the movie.”

Kiernan and his car shared the stage at the unveiling Sunday with Molly McQueen and the new 2018 Ford Mustang Bullitt edition, painted the same color, and featuring similar wheels and trim as the original, plus a souped-up engine. Molly McQueen—who followed in the family business and is a creator, producer, and star of the digital series Reasons I Don’t Have a Boyfriend—had the opportunity to drive the new car at speed in a promotional video, and though she wasn’t previously an automotive fanatic, she found herself compelled by the opportunity. “I’ve always been an adrenaline junkie,” she said. “So I felt like they awoke a sleeping beast in me.”

Kiernan had a more somber response to seeing the new Bullitt Mustang united with the one his father owned for 40 years. “I feel it’s almost a dedication to dad,” he said. “It’s a dedication to the movie as well. But when I see my car, I see my dad.”

Correction (5:22 P.M.): Due to an editing error, when first published the headline of this story incorrectly stated that the car was up for auction. It is not.