Benedict Cumberbatch believes he could’ve been patient zero of the coronavirus pandemic.

The Academy Award-nominated actor is taking a closer look at the mysterious illness that left him nearly incapacitated in 2019. After going over his symptoms, he now believes he was among the first people to contract the deadly COVID-19 disease.

“I was incredibly ill to the point that when all this COVID stuff suddenly broke in the new year,” Cumberbatch revealed to The Independent.

After reading early reports about the pandemic, the 44-year-old “Dr. Strange” star expressed concern that he could have contributed to the outbreak, telling the publication, “I was thinking, ‘Oh my god, was I actually patient zero.’”

The London-born actor had flown to Cape Town, South Africa, toward the end of 2019 to film his movie “The Mauritanian” when he was struck by the mysterious illness.

“I was so ill — it was borderline pneumonia,” he described, saying he powered through the sickness to complete filming despite “throwing up between takes.”

Illness aside, Cumberbatch said working on the Kevin Macdonald-helmed legal drama opened his eyes about Guantanamo Bay, the U.S. military prison near Cuba that was established after the 9/11 attacks to house terrorism suspects.

After filming the movie, which is based off the memoir “Guantanamo Diary” written by former detainee Mohamedou Ould Slahi, Cumberbatch says he is joining the efforts to have the detainment center shut down.

The 44-year-old classically trained thespian — who was happy to have the chance to work with “one of (his) all-time heroines” Jodie Foster — said he plans to reach out to President Joe Biden about shuttering Guantanamo.

“I’m going to plead with the guy. It is a huge spend. It’s the most expensive prison on Earth,” he said. “I feel quite strongly that Guantanamo doesn’t have a place in our world.”