The TV mogul says he's lost over four stone thanks to his new healthy lifestyle.
Simon Cowell, who turned 60 this year, has been looking slimmer and younger ever since he adopted a vegan diet. He says he has never been healthier after ditching meat and dairy products.
In his latest interview on tv show Extra, he told Terri Seymour: "I think I have dropped, since I started this diet a year ago, 60 pounds."
He said that following a healthy lifestyle is much easier when staying at home during the coronavirus lockdown. He says he's been exercising more and cooking healthy meals now.
The only food temptation that triggers him is when his son Eric wants to order pizza.
He said: "I'm doing a bit of cooking. I'm exercising. Funny enough, more during this time as well, sticking to the diet."
"The only difficult thing is when Eric orders a pizza… That's the number one thing I miss," he added.
Britain's Got Talent judge shared his tips on how to stay in a positive mood and survive the quarantine.
He said: "Most importantly, occupy your mind. You have to stick to a routine. Fortunately, with things like with Zoom, you stay in touch with the world, keep motivated, come up with ideas... I never get this time, normally."
Cowell is spending time bonding with his family during the lockdown. Initially, he was worried about how his son was going to cope with the new situation.
He said: "I was concerned how Eric was going to cope with all of this. He has been absolutely amazing. He is still able to do schoolwork, and now we are camping on the weekends in the garden."
Cowell also revealed that he planned to release a cookbook inspired by his incredible transformation.
He said: "It's something I have been thinking about because everyone's so interested. I think I would call it, It's Not That Difficult.
"I'd give people some of the recipes I have been following. What you eat has to taste nice - otherwise, you won't stick to it."