Writer Tom Bower is planning a sequel to his revealing biography of Simon Cowell - and he said the X Factor boss has already agreed to talk to him.
Bower's unauthorised book, published last week, was assembled from hundreds of hours of conversations with the media mogul.
The journalist said Cowell had conceded some of the revelations were "embarrassing," but they "remain friends".
The biography, Sweet Revenge, detailed the millionaire TV and music boss's affair with Dannii Minogue and unflattering comments about X Factor judges and contestants as it gave an insight into his life.
He told ITV1's This Morning that he had spoken to Cowell since the contents became public.
"The first call was 'you are getting a lot of publicity for your book'.
He said 'it's a bit embarrassing, you got things I didn't know you'd got'. But we get on very well. Finally he said to me last night, 'we remain friends'."
Bower said he was contacted "out of the blue" by Cowell when he heard he was working on a book about him and agreed to cooperate.
"It was a very, very interesting journey. There is a man who's actually very private in his life although he doesn't seem it. He keeps his secrets pretty well.
"I flew with him a lot to America on his private jet, I was on his yacht, visited him often in his house in LA. I got to know him very well and we got on very well. In the end I reported what I found."
He said there would be enough material for a second book. "Oh yes, there will be a sequel. He'll be with us for a long time I think," Bower confirmed.
Asked whether Cowell would speak to him for the follow-up, he said: "I think he will. He said last night that he will."
Bower said that despite building up a close relationship with the 52-year-old, he still had to "dig" to find out more about the women in his life.
"He didn't hand it out to me. He made me go and do what journalists do, which is dig.
"Then I confronted him with some things - and other things I wouldn't tell him about."
The first Cowell knew of the book's content was when he read the newspaper serialisation, Bower said.
And the writer explained that he felt there were some details which should not be included in the book.
"There are a couple of things. I got so close to him there were times he would say things, do things ... we were so close I was privileged to see things. I thought that was so private, I wouldn't abuse my facility. That was something I really shouldn't put in the book," Bower said.
"I would sit with him until 3am or 4am. For example, when he said Cheryl and Dannii Minogue were his toys, he wouldn't have realised how explosive that was and I can assure you I didn't tell him. I just noted it.
"He doesn't really know what I have got. If you talk for so many hundreds of hours you don't keep a check."
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