Billy Bob Thornton Has the Rarest Blood Type on Earth — and It Explains His Extreme Diet

Billy Bob Thornton has always been one of Hollywood's more eccentric personalities — the kind of man who once famously wore a vial of Angelina Jolie's blood around his neck, who is terrified of antique furniture, and who spent years doing drastic body transformations for film roles. So when he sat down on Howie Mandel's podcast Howie Mandel Does Stuff recently and started talking about his diet, nobody was entirely surprised to find it was complicated.

What surprised people was just how restricted it actually is — and the rare medical reason behind it.

The Blood Type Nobody Has

Thornton, 70, told Mandel that he has AB-negative blood — the rarest blood type on earth. Fewer than 1% of the global population carries it. In the United States, the American Red Cross identifies AB-negative as the least common blood type among Americans.

"I have type AB-negative blood, which is the rarest type in the world," Thornton said. "It means you have less digestive enzymes. That's one of the things that goes along with it."

The connection between blood type and digestive function is part of what's known as the Blood Type Diet — a concept popularized by naturopath Dr. Peter J. D'Adamo, who argues that people with type AB blood tend to have low stomach acid and digest food differently than other blood types. It's worth noting that no peer-reviewed studies have established a clear scientific link between blood type and dietary needs. But Thornton says his experience tracks with the theory — and his lifelong history of food allergies has kept him on a restricted path regardless of the science.

What He Can't Eat

The list is long enough that Howie Mandel, after hearing it, had a pretty reasonable reaction.

"You've just listed the entire pyramid," Mandel said.

No dairy. No wheat. No shellfish. No pork. No beef. No red meat of any kind. Thornton said he grew up eating everything without understanding why he always felt terrible afterward.

"I just assumed everybody felt like that after they ate," he said. "I didn't know."

It wasn't until the late 1980s that Thornton learned about his rare blood type and began eliminating the foods he'd been eating his whole life. In a 2020 podcast interview, he described himself as "a vegan who cheats — but I don't cheat that bad." That framing still holds. At home, he said, his options open up considerably — gluten-free chips, dairy-free cream cheese, and other substitutes that make the restrictions more livable.

"When I get home, it's like, wide open," he told Mandel.

The Grape and the Dijon Mustard

The best part of the interview — and the part that spread fastest online — involved what happened when Thornton showed up to a Landman Q&A event alongside costar Sam Elliott and found nothing in the green room he could actually eat.

The spread was a classic Hollywood pre-event table: salami, prosciutto, crackers, starchy things. All off limits. He scanned the room and spotted a small cluster of grapes sitting in the middle of the cracker tray.

He took a white grape. He looked at the table. He spotted some Dijon mustard.

"I dipped this grape in the Dijon mustard," he said. "It was one of the best things I ever had in my lifetime. So now it's become a thing for me."

The Landman Connection

Thornton is currently starring in Landman, the Paramount+ drama about roughnecks and billionaires in the West Texas oil industry. The show also stars Ali Larter, Demi Moore, and Sam Elliott — the same Sam Elliott who was standing nearby when the grape-and-Dijon incident unfolded.

Thornton has spoken warmly about the series and what it taught him about a world he thought he knew. "I knew some about the oil business," he told Fox News Digital in November 2025, "but I knew people more on the suit side of it. One of the things that surprised me was how many people who had broken lives are working in the oil fields — ex-cons and all kinds of things — because they can make $120,000 to $180,000 a year."

The diet restrictions apparently haven't slowed him down. At 70, he's still working at the same pace he always has — just with a more carefully curated snack situation backstage.

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