Billy Bob Thornton (NBC / Getty Images)

'Landman' Star Reveals He Suffers from Rare Health Condition

Landman star Billy Bob Thornton recently revealed that he suffers from a rare health condition. It affects his everyday life, especially what he eats.

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Thornton appeared on Howie Mandel's podcast, Howie Mandel Does Stuff. The Landman star revealed he has to have a restricitve diet due to allergies he has.

"Well, I'm allergic to wheat, dairy. I have type AB-negative blood, which is the rarest type in the world. It's, like, less than 1% of the population of the world has it," Thornton explained. Less than a percent of the population in the country have AB-negative blood. His blood type has caused him to have a delicate stomach.

"It means you have less digestive enzymes. That's one of the things that goes along with it," he said. Thornton says that he grew up with allergies but felt terrible. "I just assumed everybody felt like s--- after they ate. I didn't know. But anyway, I can't have dairy, wheat... can't eat meat, like, you know, pork or beef or any of that stuff."

'Landman' Star Talks Diet

Thornton began to change his diet in the late 1980s. He started eliminating wheat and red meat as well as dairy products from his diet. The Landman star also talked snacking with Sam Elliott as well.

"We were at this place, and normally in these green rooms, they got a spread. You can usually find something," Thornton said.. "And they had one little silver tray that was nothing but like salami and prosciutto and another tray full of crackers and stuff that I couldn't ... all the starchy things were over here on this tray. But that's all they had. And I'm like, 'Well, s---. I can't have any of this.' "

"But in the middle of the cracker thing, they had some grapes," he continued. "And I got a white grape. I'm like, 'Okay, so I'll be bored as hell with this.' And then I saw some spicy Dijon mustard and I thought, 'Now, I wonder.' "

Thornton ate a grape with mustard. It became his new favorite snack.