‘The Crown’ star Claire Foy says she had internal parasites for ‘at least five years’

Claire Foy poses for photographers upon arrival at the premiere of the film "H is for Hawk" during the London film festival in London, Sunday, Oct. 12, 2025. (Photo by Scott A Garfitt/Invision/AP)

Claire Foy has revealed that she had to change her diet after finding out that she was housing some unwanted guests.

Speaking on the “Table Manners” podcast on Wednesday, the “The Crown” star told hosts Jessie and Lennie Ware that she had given up drinking caffeine, before going on to explain why.

“Quite a few years ago, I had parasites. Gross,” she said.

“I kept losing weight and I didn’t know what was going on,” said Foy, 41, who said she thinks she picked up the parasites in Morocco, and had them for “at least five years” before she found out.

“They travel as a pair, I got told by the doctor. Gross, absolutely rank. It’s disgusting,” said Foy, who is best known for playing Queen Elizabeth II in the hit Netflix series “The Crown,” as well as for roles in the BBC dramas “Wolf Hall” and “A Very British Scandal.”

She then made changes to her diet to treat the parasites, she said, as she “didn’t want to take really hardcore antibiotics.”

“I took all this little gross stuff, and part of that was giving up caffeine,” she said, admitting that it wasn’t easy to do so, as someone who used to drink “at least 15 cups of tea a day.”

Foy went on to reveal that she also restricts her diet due to an autoimmune condition.

“This is my big secret, I feel like I’m in ‘The Traitors’ or something, and I’m letting everyone know that I’m related to someone,” she joked.

“I don’t actually eat gluten or sugar … except when I go out for dinner.”

Foy said that she is “very strict but I love falling off the wagon when I’m out for dinner,” adding that she isn’t allergic.

“It doesn’t have an impact on me. It’s just because I have an autoimmune condition, so I should avoid anything which causes more inflammation,” she said.

By Jack Guy, CNN