Sinitta has admitted she was "utterly stunned" when she found out her ex and close friend Simon Cowell was to be a dad.
The TV mogul is expecting a baby with New York socialite Lauren Silverman, and called the singer and former X Factor mentor to tell her the news.
She told Hello! magazine: "I was completely and utterly stunned. I was in such a daze, to the point where I wondered if I was dreaming it.
"He sounded... odd, calm, strange, which threw me. I don't mind admitting all sorts of emotions were running around inside me. He was very concerned about how I would take it, which, on reflection, he didn't need to be. He didn't owe me that consideration."
Sinitta, who has two adopted children, went on: "I suppose there has been a certain amount of comfort for me in my not having a child with Simon because he never wanted to have children at all. That's who he was, so you accepted it.
"Then, to discover that he is going to have a child, only with someone else and they're building this life together... All those crazy things were going through my head and it's not fair and it's not pertinent to Simon and Lauren's situation and I don't have a right to feel that way. But I'm being honest."
The 49-year-old, who dated Simon in the 80s and has remained close friends with the star, also confessed that she felt "a sense of betrayal" when she realised that he had fallen for Lauren.
"We knew we were all close friends but I didn't realise he and Lauren were falling in love and, when I found out, I will admit I was taken aback and did feel a sense of betrayal," she said.
In July, Sinitta tweeted a cryptic message that she has now confirmed was referring to Simon's baby announcement.
It said: "Something has just happened ... half miracle, half nightmare! #WakeMeUpIWantToGetOff!!"