Jim Parsons told Jimmy Fallon on Monday during a video interview that he and Todd Spiewak tested positive for COVID-19 in mid-March.

"The Big Bang Theory" star admitted that not everyone knew that they fell ill. He thought now would be a good time to share his experience with the disease.

"Why not talk about it with you on television?" Parsons said during his appearance on Fallon's "The Tonight Show."

The comedian said he and Spiewak did not know that they had COVID-19 at first. They thought they only had colds.

"Then it seemed less likely and then finally we lost our sense of smell and taste. Utterly. It defied the descriptions for me. I didn't realise how completely taste and smell could be gone," Parsons continued.

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Given the sentimental mood of our final taping, I am just mushy enough to post a pic of me and Todd from a party at Johnnys house after we shot the original, unaired pilot of Big Bang back in 2006. I’m also mushy enough to send a very specific Thank You to Todd who has truly been my main source of sanity and gravity through this whole wonderful yet crazy journey of the last 12 years.. I absolutely would not have been able to do it without him. No exaggeration. I love u, Todd! ❤️ (thank you for indulging my sentimental evening and love to u all❤️)

A post shared by Jim Parsons (@therealjimparsons) on

The 47-year-old "Young Sheldon" actor also talked about his time in quarantine. He joked about how there was nothing else to do but eat, which he considered "brutal." When Fallon asked if it was brutal because he did not feel like eating anything and that everything for him was "gross," Parsons revealed that he still "ate everything" even though he could not taste anything. The admission made Fallon laugh.

"It was the definition of wasted calories," the actor said.

Parsons also shared that during his recovery from COVID-19 and quarantine period, he tried out new hobbies including creative writing and painting. He took both classes for a while until "everything petered out."

"I don't know if the truth is, 'Well you're just an actor, and that's what you do and that's what you should do,' or if it's just I really don't have the see-through stick-to-it-ness for anything," he explained.

On the bright side, Parsons did get his wish to have blonde hair, which he had wanted after "The Big Bang Theory" ended. He could not go to a salon given he and Spiewak were on quarantine. Instead, his husband bleached his hair for him and it took six hours to finish.

Parsons is one of the celebrities who just recently talked about having COVID-19 months after testing positive for the disease. Neil Patrick Harris also revealed earlier this month that he, his husband, and two children got the disease in late March.

Jim Parsons
Jim Parsons (R) and his partner Todd Spiewak pose at the 2016 GLSEN Respect Awards on 21 October 2016 Mario Anzuoni/Reuters