"Jurassic Park" star Sam Neill revealed that his doctor initially misdiagnosed his stage 3 blood cancer as a case of "undetected COVID."

The 75-year-old actor, who plays Dr. Alan Grant in the "Jurassic Park" franchise, shared that he consulted his doctor in Sydney, Australia, after becoming concerned about his swollen glands while on a press tour for the 2022 movie "Jurassic Park: World Dominion."

"At the beginning of March 2022 I flew to Los Angeles on matters ‘Jurassic,'" Neill wrote in his new memoir "Did I Ever Tell You This?" "About eight of the cast had an entire three-day weekend doing interviews, photo spreads for Vanity Fair and all of that stuff — publicity.

sam neil red carpet

"Jurassic Park" star Sam Neill revealed that his doctor initially misdiagnosed his stage 3 blood cancer as a case of "undetected COVID." (Manuel Romano/NurPhoto via Getty Images)

"It was a blast to catch up with my idiot friends and goof around as per. I noticed the glands seemed to be up in my neck region, but gave it very little thought. My agent had to kill a few photographs because my neck looked lumpy. Alan Grant doesn't have a lumpy neck, it seems."

SAM NEILL ASSURES FANS HE'S ‘ALIVE AND WELL’ AND IN REMISSION AFTER HIS CANCER NEWS

After returning to Sydney, Neil visited his doctor after becoming concerned when his symptoms weren't improving.

"I said, 'These lumps don't seem to be going down, and I don't know why,'" the New Zealand performer recalled. "He assured me that my lumpy glands were due to undetected COVID, and they'd be hanging around for a little while. I went back a week later when they were even bigger. This time he sent me in to hospital for some tests."

The three-time Golden Globe nominee subsequently underwent a PET scan that determined he had stage 3 angioimmunoblastic T-cell lymphoma.

Sam Neill in Jurassic Park III

The 75-year-old actor, who played Dr. Alan Grant in the "Jurassic Park" franchise, shared that he consulted his doctor in Sydney, Australia, after becoming concerned about his swollen glands while on a press tour for the 2022 movie "Jurassic Park: World Dominion."  (Universal)

"Within a few days, I was lying on a hospital bed having all kinds of chemicals draining into my system, killing everything aboard," Neill recalled. "For therapeutic reasons. To be cured of a thing I didn't know I had just a few days ago. Yep, suddenly things are different — this is some serious s---."

Neill revealed that he began losing his hair after the first of his four rounds of chemotherapy. 

"After my first chemo, it took only a little over two weeks for the hair to disappear completely from the top of my head," he wrote. "My brother was unkind enough to say, as we FaceTimed, Black men look cool bald, but white men look like some giant's thumb. I am no exception.

"I look like a boiled egg that's been sitting around in the pot long after the water has dried up," Neill added. "Someone has peeled that egg, but not very well."

The actor decided to shave his beard after noticing that his facial hair was falling out.

"I've had a beard for quite some time, and this has meant I haven't seen my own face for many years," Neill wrote. "Fifteen years, I'm thinking. And here was my face, now entirely unadorned. This was no small shock. Time has not been kind to it in the meantime. I'm not just wrinkled in the space where there formerly resided a beard, I am positively wizened. Three or four strokes of my trimmer and I had aged twenty years."

Sam Neill "Blackbird" premiere

After returning to Sydney, Neill visited his doctor after becoming concerned when his symptoms weren't improving. (Emma McIntyre)

Though Neill's second PET scan indicated that the chemotherapy was working, his third scan detected that the tumors had returned.

At that point, the "Peaker Blinders" alum switched chemotherapy drugs at the direction of his doctor. Though he recalled that his fourth round of chemotherapy "got a bit bumpy," Neill was eager to get back to work. He began voiceover work on a TV show but was frustrated by his weakened condition.

"I started recording a major series, 10 hourly parts, and my voice simply ran out on episode two," he recalled. "This was something of a psychological blow. I've never not finished a day's work before, never. Rightly or wrongly, it made me feel enfeebled."

After his doctor determined that his throat was ulcerated, Neill wrote that he began taking injections of "who knows what," which resulted in night sweats.

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However, Neill learned that he was in full metabolic remission following his fourth scan. He wrote, "Now I'm a living man, with every intent of going on living and living and living."

Though his treatment was difficult, the father of four said he kept a positive attitude. 

"I am still optimistic, and this optimism is maximised when I do a bit of a dance around the place," Neil wrote. "To the right music, of course."

On Sunday, Neill shared an Instagram video to update fans on his condition.

"My news seems to be all over the news at the moment, and it’s sort of ‘Cancer! Cancer! Cancer!’ Which is slightly tiresome because, as you see, I am alive and well. And I have been in remission for eight months, which feels really good," he said.

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"And I’m alive and kicking, and I’m going to work," said Neill, wearing a white T-shirt and a full beard.

He added that he is "very happy to be going back to work," explaining that, in a week, he’ll begin shooting a film called "Apples Never Fall" with Annette Benning.