The 62-year-old actor has revealed he hates using shampoo because he thinks it makes his hair look frizzy, adding that soap is the only product he ever uses.
He confessed on the 'Homo Sapiens' podcast: "It's been about seven or eight years now, I don't use shampoo.
"I just stand under a shower. Water. That's the best way.
"All you people who use shampoo and conditioner, all you do is strip all the oils out and make it ridiculously flyaway with shampoo.
"And skin is a similar thing. This obsession with micro/bio gut, there's also the skin as well.
"I haven't been one for chemicals on me - skin creams and grooming and after shave, never been one for it.
"And I think it does make your skin very good, but soap occasionally, and Castile soap, it's a more natural soap, that doesn't lather as much."
Meanwhile, Stephen recently admitted he felt "undesirable" when he first arrived on the gay scene in London in the 1980s.
The comedy star - who has been married to Elliott Spencer since 2015 - struggled to adapt when he first moved from Norfolk to the city.
He shared: "We'd go to Heaven and various other gay clubs and a sweet gay bar in Chelsea, The Queen's Head. And I didn't mind the little old pub but the look up and down sweeping eyes as you walk into a club and, in my case, the look up and down and the quick turn away.
"I'm such an undesirable person. I'm as far from cute as it's possible to be. Not that I particularly wanted to be but it was just ... also I just don't like dance places, I just like talking."