While he made a complete recovery, Sheen warned that it was far from what he expected it to be, and was wiped out by it.
Speaking on Lorraine this Tuesday, Sheen explained: “I had it back in February. Yeah, it was rough.
“I remember thinking 'Oh, I'm going to have a couple of weeks in bed reading and watching TV”, and that was not what it was like.”
“It was very rough, and I was in America at the time as well so I suddenly felt the vulnerability of not having our national health service to rely on and kind of look after me,” he continued.
“That was quite scary. I had a renewed sense of love and respect for what we have in this country, but I'm fine now.”
Welsh actor Sheen was praised for keeping spirits up during the first and second UK lockdowns with the creation of sitcom Staged, a Zoom-based series with long-time friend, David Tennant.
Filming themselves from their home, the duo played fictional versions of themselves squabbling over rehearsals while in lockdown.
He’s also been widely praised for his role in the sadly cancelled Prodigal Son in the States, where he plays serial killer Dr Martin Whitly, the father of criminal psychologist Malcolm (The Walking Dead’s Tom Payne).
Now, he is launching a new writers initiative called A Writing Chance, which aims to help those from working-class backgrounds start their careers in the film and television industry.
Choosing 11 up-and-coming writers to mentor, Sheen said: “I mean we all tell stories about who we are as a country, as a society. We want to tell a really engaging story we need to hear from everybody, in order to try and find and support those from underprivileged backgrounds.”
He added: “They're an amazing group and we're going to support them and see what happens, and hopefully we can apply to the thousands who can breakthrough.”
WATCH: Michael Sheen reads the poetry of Dylan Thomas at the National Theatre