Simon Cowell's mother is said to be 'delighted' by news that the media mogul is expecting his first child with Lauren Silverman and believes he will make a ''fantastic father''.

The 53-year-old creator of Britain's Got Talent and The X Factor is reportedly having a baby with the New York socialite, who is the estranged wife of his friend Andrew Silverman.

Silverman is said to be "around 10 weeks along".

But despite the complex circumstances surrounding the pregnancy, Cowell's mother Julie Brett says she is looking forward to becoming a grandmother.

She told The Sun newspaper: ''I've not heard anything officially. But if it's true then I'm absolutely delighted. It's wonderful! He'll make a fantastic father. He'll be great.''

Mr Silverman, a real estate mogul, reportedly filed for divorce on 15 July and is believed to have put in his affidavit on 24 July. The estranged couple also have a seven-year-old son, Adam.

"Lauren and Andrew have been unhappy in their marriage for some time, and their divorce has been in the works for a while," a source told the publication.

"As their marriage deteriorated, she and Simon became close," the undisclosed source added.

But while Brett has shared her excitement, Cowell's former flame and confidante, 80s pop star Sinitta, apparently reacted with shock and horror.

Writing on her Twitter page two days before the pregnancy became public, she exclaimed: "Something has just happened...half miracle, half nightmare!"

Britain's Got Talent judge David Walliams was able to make light of the situation, telling his fans on twitter: "Oh yeah, and @SimonCowell is doing a baby with a lady."

He later joked: "For the record @SimonCowell and I tried to have a baby together for many years. But I just couldn't get pregnant."