Brian Cox turned to marijuana to ease the stress of lockdown.
The 74-year-old actor spent March to June quarantining with wife Nicole Ansari and their sons Orson, 18, and Torin, 16, at their house on the New York/Massachusetts border, and he admitted being confined to one place with two teenagers was difficult, so he used the drug at the end of each day to relax.
Speaking to The Times Weekend magazine, he said: "Marijuana is legal in Massachusetts, and lockdown was quite stressful with the boys.
"It was difficult for them; they're city boys, not country bumpkins. My elder son had to have his high-school graduation on Zoom, then my younger son was attending a summer school and had to be up at 8am, but he'd be up until 5am every night on his device.
"So cannabis at the end of the day was very nice."
The 'Succession' star - who also has two adult children from his first marriage - admitted he used to "avoid" the drug and only discovered its benefits when he turned 50 and needed something to help him wind down at the end of a hectic day.
He said: "I avoided it like the plague. Other people were going nuts for it, but I felt it was a diversion.
"I'd married at 21; I was very responsible. I'd see people go on stage stoned and think, 'No, that's not clever!'
"But when I was 50 I was doing a play that was quite stressful, and, because I'm not really a drinker, I found cannabis fantastic to focus the day's events and prepare me for the best night's sleep imaginable."
Brian and Nicole are now back at their apartment in Brooklyn, where they sleep in separate bedrooms but meet in another studio room on a separate floor for sex.
He confirmed: "Yeah, that's what we do."
The veteran actor - who is diabetic - was "amazed" earlier this year to test positive for coronavirus antibodies and believes he contracted it at the end of 2019.
He said: "I was amazed. My family all had tested negative, so I couldn't work out when I'd had it. Then I realised it must have been in December after another visit to Scotland, when afterwards I had these sneezing fits. My doctor said, 'That's a symptom - three of my coronavirus patients had those.' "