Christie’s sale of vintage automobiles in Monterey, Calif., includes one sexy property: Steve McQueen’s 1963 Ferrari 250 GT Berlinetta Lusso. “This is an exceptional motorcar,” Christie’s auto expert, Christopher Sanger, said. “The best Lusso out there.” But what makes the McQueen Ferrari exceptional is that the auctioneers are not quite sure which is the bigger draw — the star’s name or the sports car itself.

This means that the likely buyer of the car, estimated to sell for between $800,000 and $1,200,000, is either a Ferrari nut who just has to have this pristinely restored classic, a conspicuous consumer who thinks the $395,000 Saleen S7 — the world’s current most expensive sports car — is too showy but not pricey enough, or someone living out his “Thomas Crown Affair” fantasies.

In 1963, Steve McQueen (1930–80) finally became a movie star. He’d been trying hard for several years. Despite studying at the Actors Studio, McQueen didn’t get much work until his wife — the dancer Neile Adams — pushed her agents to get him a job. What he got seemed like an unpromising television western. The role of the cool, detached cowboy led to some film roles like “The Magnificent Seven.” Then came the breakout of “The Great Escape,” in which McQueen’s character, known as “The Cooler King,” made that famous motorcycle leap over barbed-wire fences.

Long before McQueen became a star, he was already a confirmed speed demon, never without a fast car or motorcycle. Indeed, McQueen was sure his greatest talent lay not on the screen but at the track. Even motorheads who don’t care much for cinema know McQueen from his legendary car racing film “Le Mans” (1971) or the famous car chase in “Bullitt” (1968.) They know that Battista “Pinin” Farina, the famed maker of Ferrari coaches, designed the 250 Lusso, and it is considered one of the most beautiful examples of the true sports car — not a racing machine, but a car that takes you away fast.

And that’s what McQueen did. For 10 years, he used the car as his transportation. This Ferrari was no collector’s piece to him; only 350 were made, but some models of race cars are far more rare. A week after the chestnut-brown Ferrari was delivered McQueen and his wife took a road trip from Los Angeles to Big Sur, Carmel, Monterey, San Francisco, Reno, Lake Tahoe, down through Death Valley, and back to Los Angeles. The 1,500-mile drive was done with another couple, photographer William Claxton and his wife, who drove their own car. “We would set a place to meet for lunch and then take off,” Mr. Claxton told Motor Trend magazine a couple of years ago. “Steve’s idea of fun was to go roaring off and, a couple of hours later, be parked at the side of the road pretending to be bored waiting for us to arrive.”

The car also expresses another side of McQueen’s personality: his innate sense of understated style. McQueen was a pioneer of casual elegance. Never quite the sophisticate he played in “The Thomas Crown Affair,” he singlehandedly created a look of moneyed selfconfidence in that movie. But the Ferrari shows he already had it down half a decade earlier.

Most guys who buy a Ferrari want to be noticed. Eric Clapton owned a Ferrari 250 GT Lusso. It’s a rock star’s kind of car. That’s why so many come in red or canary yellow. Even the understated ones are in a threatening black or opulent silver. But McQueen got his in dark brown and accented it perfectly with beige leather. McQueen preferred his cars in dark colors like British racing green. But he also knew how to do that tonal thing for subtle, eye-catching effect. (For reference, notice the clothes in “The Thomas Crown Affair,” especially the pale blue shirt with royal blue tie under a Prince of Wales checked suit with a light blue overplaid.)

“I’ve sold a red Lusso and a silver Lusso,” Mr. Sanger said. “But this color transforms that car. I’ve never seen another car in that color.” If McQueen had never owned the car, it could be worth between $550,000 and $650,000 — or much more, Mr. Sanger added. A car with such perfect styling, so meticulously restored is a rare gem. It’s provenance just makes it that much more valuable.