Simon Cowell has admitted in a new interview to being “selfish and weird” – and also confessed that he is still haunted by his insecurities.

Speaking to Oprah Winfrey, the The X Factor mogul said that he still fears every time one of his programmes is shown it will be a flop and his career will be over.

“Doing these shows is relentless,” he said. “When the ratings come in you’re happy for five minutes then insecure madness comes in and you worry about next week. The minute I think we can do better I’m out.

However, he credited his fiancee Mezghan Husseiny for helping him cope.

“Mish has softened me,” Cowell said. “She’s helped me see the world differently. She has knocked my socks off. I’d never been good at relationships. I never thought I’d be with one person – now I think I will.

“I genuinely believed no-one would want to marry me. I am difficult to live with. I’m selfish, quite weird, and I need time on my own to think – and then I work all night long.”

“That is difficult for someone to deal with,” he said. “And it would drive me mad – I could never be my own girlfriend.

“I’m also terribly moody. When I’m in those moments, and I get down, I feel like going into hibernation. I’m like a bear in a cave – ‘Don’t touch me!’ – and it can last days, sometimes weeks.”

Simon also revealed his fears that time is running out for him to have a family.

“I worry about that because of my age,” he said. “When I was younger my dad used to play soccer and games with me. And I worry that if I was 70…also if children could be born at the age of five I’d quite like that, when they can talk and understand.

“I’m not sure I could deal with the whole ‘ga ga goo’ thing. But I genuinely like kids.”