The “Antiques Roadshow” guest kept his cool as an appraiser said his watch, snagged decades ago in the Air Force, was no ordinary Rolex. Informed that it was a lot like a model once worn by Paul Newman that auctions for $200,000, the camouflage-bandanna-clad owner just nodded.

Then the appraiser noted the tiny word Oyster inscribed on the face. That made the trinket “extremely, extremely rare,” the kind of watch that sells for $400,000.

The man toppled backward to the ground with enough force that his feet flew up into the air.

There was laughter and a mildly concerned “You okay?” — but also more good news to come. The Rolex was also in near-perfect condition, the grinning watch owner heard next. The discount purchase that set him back $345.97 in 1974 — in the range of a month’s military salary — was now worth between $500,000 and $700,000.

Appraiser Peter Planes declared it one of the greatest watches he had ever seen on “Antiques Roadshow,” now in its 24th season. The moment, filmed on tour in Bonanzaville, a pioneer village in West Fargo, N.D., would top the season’s finds and delight staff who say they’ve never seen a guest literally floored, even on a TV show that thrives on stunning people with the value of objects often tucked away for years.

“Half a million dollars, 700,000 dollars — that’s life-changing for somebody,” Planes told The Washington Post.

The watch owner, whom “Antiques Roadshow” has identified only as David, greeted the final dollar estimate with closed eyes and a word that was bleeped out.

David explained on Monday’s show that he became interested in a Rolex while stationed in Thailand in the 1970s, working to clear roads of land mines and clean up munition storage spots. He noticed that airline pilots seemed to wear the watches — but they were out of his price range.

A fan of scuba diving, he said, he eventually decided to spring for a watch that could survive underwater and ordered a Rolex through his base exchange at a 10 percent discount. But when the fancy accessory arrived, he ended up locking it away in a safe-deposit box.

“I looked at it, and I said, ‘You know, this is really too nice to take down in the salty water,’ ” David said.

He claims he only took it out two or three times until the summer that “Antiques Roadshow” came to town. That’s part of what makes this particular Oyster Cosmograph, also known as a Daytona, so valuable, according to Planes, who specializes in high-end timepieces and estate jewelry as the owner of Florida-based Luxe Auctioneers. The numbered foil sticker on the Daytona’s back, normally the first thing to wear off, was still intact.

Also a boon, he said: the fact that Newman popularized the Daytona Rolex in the 1969 drama “Winning.” The watch became intertwined with the actor and racecar driver’s image, as Travis Andrews reported for The Post:

The mechanical watch radiated coolness, much like its owner. It was a constant companion to Newman’s left wrist in magazine shoots, paparazzi photos and while he was speeding around in his racecars. The model, which was “made famous by him thanks to this very timepiece,” was eventually nicknamed the “Paul Newman Daytona,” Phillips Auction House said in a news release.

Newman’s actual watch was auctioned off in 2017 for $17,752,500, a world record, after 12 minutes of bidding.

The “Antiques Roadshow” guest’s watch may not have graced a star’s wrist, but it’s actually more special than the model Newman wore, Planes told David. The word “Oyster” indicates that this accessory had a particularly water-resistant case, he said.

And with the immaculate conditions and saved paperwork to boot — the blank warranty paper alone is probably worth about $2,000, Planes guessed — the watch was a season highlight. “Antiques Roadshow” says the watch is its highest-valued Rolex, while the most expensive watch seen on the show has an updated valuation of between $2 million and $3 million.

Some guests have muted reactions, Planes said. Others can barely keep their composure. One man, he remembers, began to cry and needed some Kleenex. But David’s collapse stands out.

As for what the guest may do with his newfound wealth, Planes said he’s not sure. He never asks guests about their plans, and for all he knows, the man may keep it locked up.

“He’s saved it all these years,” Planes said. “He may be saving it more.”

Indeed, the takeaway from Monday’s episode may be to refrain from wearing your watches, said Marsha Bemko, the show’s longtime executive producer. She said she’s viewed the “delicious” segment with the Daytona timepiece over and over.

“My heart still jumps,” she said.

Antiques Roadshow airs on Mondays at 8 p.m. Eastern time on PBS.

Correction: This article previously stated that Monday was the kickoff of the show’s 24th season. In fact, it was the kickoff of episodes from Bonanzaville.

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