William Shatner is using cannabis extracts to treat his "aches and pains" brought on by age.
The Star Trek star, 89, described the treatment as "magical" and said he had been using it to soothe his swollen joints.
CBD and THC are compounds known as cannabinoids, found in the cannabis plant, and are legal in parts of the United States under certain conditions.
Shatner told the PA news agency: "I've got some aches and pains I didn't have a few years ago.
"But, I'm finding out there are many things that help aches and pains that we didn't know about just a few years ago. Well, THC and CBD, and that kind of thing."
He added: "Have you used it? It's magical. I've had swollen joints where it hurts, you rub some on and while you're rubbing it on, the pain disappears. It's magical."
Shatner is returning to host another series of The UnXplained, a non-fiction programme that explores fascinating and strange mysteries.
He added: "There are things around us that we haven't discovered yet which seemingly are mysterious but then we find an explanation.
"Human beings are constantly searching, you and I are constantly searching answers to make a good pie. You know, what constitutes a good blood pudding? Or chicken pot pie…"
The UnXplained premieres on Sky History on Tuesday at 9pm.
All episodes will be available on catch-up services. Sky History is available on Sky, Virgin, BT, Talk Talk and Sky's Now TV.