Simon Cowell has admitted he is "not proud" of the way he treated American Idol contestants during his early years on the show.

The British TV personality and record executive has reflected on the harsh critiques that helped turn him into a household name when the series launched in 2002.

Speaking to The New York Times, Cowell - who became known for his cutting put-downs - acknowledged that he had taken it "too far".

He explained that he had been driven by pressure to find real talent and feared the programme would be cancelled if it failed to deliver.

"When I used to do auditions, someone would come in and they can't sing, we would say after 10 seconds, 'You can't sing,' not, 'You're going to be brilliant,' and everything else," he stated. "So I was frustrated at the beginning, because I thought, if we don't find someone good at the end of these shows, they're not going to get recommissioned."

The interviewer noted that YouTube is full of compilations of Cowell insulting contestants, including remarks about their appearance.

"Do we have to go through this?" Cowell asked. "I've got to be honest with you. That's why I did change over time. I mean, I did realise I've probably gone too far."

"I didn't particularly like, I still don't like, audition days because they're long and boring," he continued. "I would get fed up. And of course, you know, out of 100 nice comments, what are they going to use? They're always going to use, you know, me being in a bad mood."

The America's Got Talent judge went on to apologise for his past behaviour, saying, "What can I say? I'm sorry."

Asked what exactly he was apologising for, he replied, "Just being a d**k ... I'm not proud of it. Let's put it that way. I never look at this stuff online or anything. You know, I'm not someone who particularly wants to see myself on camera."

"So when I hear about these clips, I'm like, 'Oh God,'" he continued. "But then again, the upside is, I suppose, with these clips, is that it made the shows really popular worldwide."

Cowell is currently promoting his new Netflix series Simon Cowell: The Next Act, which is set to launch on 10 December.