Simon Cowell revealed he has "millions" of regrets, but they don't "eat him up".
The media mogul refused to go into detail, but admitted they include "silly business deals" and people he's "trusted", while insisting he tries not to dwell on the past too much.
Talking about regrets to fellow 'Britain's Got Talent' judge David Walliams for The Sun newspaper's TV Magazine, he said: "Millions, but that's part of life.
"When things go wrong, you own up to your mistakes and don't do it again. I'm not going to talk about my biggest regret now, but silly business deals I've done, people I've trusted. There's nothing that eats me up, I would say."
The 54-year-old father - whose partner Lauren Silverman gave birth to their son Eric in February - also admitted he was shocked at "how quickly" he settled into being a parent for the first time.
Asked what surprised him most, Simon responded: "How quickly I adapted. When you first see him there, you have this immediate protective urge.
"It just takes over you ... [But] it hasn't [changed me]. I'm still working as hard. it gives you a sense of wanting to be protective. all that kind of stuff. It's good."