Since Hagerty.com broke the news in January 2018 that the long-lost Bullitt Mustang was found in Tennessee, many classic car aficionados have speculated on the value of the rare classic car.

We shall soon know — in five months, the 1968 Ford Mustang driven by Steve McQueen is headed to Mecum’s 2020 Kissimmee auction. Company president and founder Dana Mecum made the announcement on August 14 to kick off Monterey Car Week.

Mecum says he expects the Mustang to surpass the American muscle car record of US$3.5 million for a 1971 Plymouth Hemi Cuda convertable at Mecum’s 2014 Seattle auction. The highest auction price for a Mustang to date is US$2.2 million for a 1967 Shelby GT500 Super Snake at Mecum Kissimmee earlier this year, the report said.

Estimating the value of an iconic car like the Bullitt Mustang can be difficult since it’s impossible to know just how much someone is willing to pay for a car that is so ingrained in American pop culture and has never been at auction before — particularly one that was driven by “The King of Cool” in arguably the greatest car chase in movie history.

“There really is no other car to which it can be compared,” says automotive expert and author Colin Comer. “When you put everything together — a cultural icon, connected to a movie legend, and it’s a Mustang — it really stands alone.

“Then you consider that most people thought it was long gone, destroyed, it was amazing enough when it came out of hiding 18 months ago in near-original condition. Now, for someone to actually have an opportunity to own it for themselves — a car that McQueen couldn’t even buy — this is an unprecedented historic event.”

The Highland Green pony car famously dueled a Dodge Charger on the streets of San Francisco and then disappeared. Sean Kiernan, however, knew exactly where it was.

The Mustang had already passed through the hands of at least two owners when Kiernan’s father, Bob, bought it after answering an ad in the October 1974 issue of Road & Track, the report said.

Once McQueen found out where the Mustang was and who owned it, he reached out to Kiernan on more than one occasion in an attempt to buy it for himself. But Bob Kiernan wouldn’t budge.

After his father died in 2014, Sean Kiernan and his family continued to keep the car a secret. It no longer ran and was in need of work, but as Sean explained last year, he and his dad frequently discussed bringing the car back into public view.

That happened a year and a half ago at the North American International Auto Show in Detroit. The Bullitt Mustang has been touring the country ever since.

It’s no surprise that the family labored over the decision to sell the car.

“There were a lot of sleepless nights and stress,” Sean Kiernan says. “The car is my father’s legacy. It’ll be hard looking in the garage and seeing an empty space, but at the same time this is a way for my dad to take care of his family. We’ve taken care of it and protected it, and now it’s someone else’s turn. It just seems like a good time to do it.”

According to Motor Trend, stunt legend Carey Lofton — who had worked on “Redline 7000,” the road race in “Viva Las Vegas,” and “Grand Prix” — was hired to stage the famed chase. Lofton also designed the zany/legendary car chase in “It’s a Mad, Mad, Mad, Mad World.”

“All the stunt men thought we were crazy,” remembers British director Peter Yates. “They wanted ramps for flips, crashes, and explosions. One stuntman asked me, ‘What can you do with hills?’

“Steve and I both had a great respect for cars,” adds Yates, who club raced in England and was team manager for Stirling Moss. “I admired the skills needed for driving. I didn’t want a crash derby.”

Bill Hickman, perhaps Hollywood’s finest stunt driver, was chosen to drive the Charger, Motor Trend reported.

Hickman was a close friend of James Dean and pulled Dean out of his twisted Porsche the afternoon he died in the infamous head-on crash. Hickman and McQueen tested their cars at Cotati Raceway north of San Francisco a few days before shooting the chase scenes began.

The 12-minute chase took two weeks to film — one sixth of the entire shooting schedule. McQueen definitely wanted to handle all the Mustang stunt driving.

“There really is no other car to which it can be compared,” says automotive expert and author Colin Comer. “When you put everything together — a cultural icon, connected to a movie legend, and it’s a Mustang — it really stands alone.” Handout.

Some accounts say it was pressure from his family and the studio that got him out of the car for the most difficult scenes. Eventually, it was McQueen’s inability to pull off the stunts that forced Lofton to replace him with Bud Ekins, McQueen’s longtime friend who performed the famous motorcycle jump in “The Great Escape.”

“The success of the car chase still had a lot to do with Steve even though he didn’t do the dangerous stuff,” said first assistant director Tim Zinneman.

The chase continued on the outskirts of the city toward the airport. Speeds well over 100 mph required a special camera car built by Pat Hustis. McQueen handled much of the Mustang’s high-speed driving, but Ekins worked the bumping scenes with the Charger.

Stunt driver Hustis got close enough at speed for Cinematographer William Fraker to record some dramatic shots, including the shotgun blast that was just inches away from the camera lens.

“Bullitt” opened at New York’s Radio City Music Hall Oct. 17, 1968, then was released nationwide in December, just days before Apollo VIII first circled the moon. It was a huge hit for Warner Bros. and solidified McQueen as a major Hollywood star.