John J. York is Thurston Carteprioritizing his health.

The General Hospital star shared that he will temporarily step away from the soap opera while he battles two blood and bone marrow disorders.

"So last December of '22, I was diagnosed with myelodysplastic syndromes, or MDS, and multiple smoldering myeloma," York said in a video posted to X, formerly known as Twitter, Sept. 13. "Over the past many months, I've had three bone marrow biopsies, many chemo treatments, I have another one coming up in a couple of weeks, and I'm closing in on a blood stem cell transplant."

Myelodysplastic syndromes occurs when blood-forming cells in the bone marrow become abnormal, according to the American Cancer Society. Multiple smoldering myeloma is a blood and bone marrow disorder than can serve as a precursor to multiple myeloma, a rare blood cancer, per the Cleveland Clinic.

York noted that he's been working with Be The Match, a bone marrow donation program, to "find a potential donor on their registry."

"If it's possible," the 64-year-old said, "you would consider being a donor, joining their registry, for not just me but thousands and thousands of other people who are in need of a donor."

As for his fans, York expressed thanks for "for all the support over the years," adding that he'll soon return as character Mac Scorpio to the daytime series.

"This isn't goodbye, this is just, 'So long,'" he continued. "I'll have to take a break for at least three, maybe four months, but I'll be back."

In a follow-up post, York, who first announced his brief hiatus on X Sept. 7, said he was overcome by the strong support amid his health journey.

"The OUTPOURING of kindness, concern and support has dropped me to my KNEES," he wrote. "Thank you for the OVERWHELMING EMBRACE and your interest in and support for Be The Match! The simple truth…we ALL need each other."

For the latest breaking news updates, click here to download the E! News App