The 66 year old revealed that he got the jab, a treatment which was originally designed to treat people with diabetes, from his doctor in the US "years ago".
Ozempic suppresses the appetite, and lengthens the amount of time of food which stays in the stomach, leading to weight loss, for as long as you continue to take it.
Stephen Fry told the River Cafe Table 4 podcast that he initially reaped "astonishing" results, leading him to believe that he had found a "brilliant" solution to his weight loss issues.
"I'm an early adopter of these things" Fry said. "And I happened to be in America and I'd read about it".
He continued, "I asked my doctor in America, my physician, as they like to call them, and he said, 'I think I can get you some'.
"He tried me on it and [for] the first week or so I was thinking, 'this is astonishing. Not only do I not want to eat, I don't want any alcohol of any kind. This is going to be brilliant'".
"Then I started feeling sick, and I started feeling sicker and sicker and sicker. I was literally throwing up four, five times a day and I thought, 'I can't do this'. So that's it" he added.
Ozempic has been banned as a treatment for obesity in the UK due to its high demand for the drug, causing a global shortage.