Simon Cowell and Lauren Silverman
Andrew's brother is said to have told the paper: "It is an unbelievable story of betrayal. It is a sad story and a tragic story."
Due to Andrew's claim, Simon could face being hauled into court to reveal details of his relationship with Lauren.
"It's really a signal to the spouse who cheated that the wronged spouse is very angry and that it's going to be a very nasty, scorched-earth, high-profile litigation," divorce attorney Martha Cohen Stine reportedly told the NY Post.
However, a source previously told Us Weekly that the divorce had been in the works "for a while".
"Lauren and Andrew have been unhappy in their marriage for some time, and their divorce has been in the works for a while," they said.
"As their marriage deteriorated, she and Simon became close."
According to the magazine, New York socialite Lauren is around ten weeks pregnant with Simon's baby.
Simon Cowell leaves X Factor USA auditions on Wednesday
The music mogul was pictured for the first time since the reports emerged leaving 'X Factor USA' auditions in LA on Thursday night, where he made no comment to reporters at the scene in a video captured by the Daily Mail.
While Simon is yet to comment on the news, with his lawyers also offering no comment, his mother Julie has reportedly told The Sun she is "delighted" at the "wonderful" news.
Close friend Sinitta has also appeared to react to the news on Twitter, writing: "Something has just happened ..half miracle, half nightmare! #WakeMeUpIWantToGetOff!!"
'X Factor' judge Sharon Osbourne also said: "I know they’ve been friends for a while, for a few years, and it happens doesn’t it. I do think he’ll be a great father. He is so good with children and people don’t know that about him"
1. Nobody seems to know whether she's called Lauren or Laura. Or both. So let's get this one cleared up once and for all. It's definitely LAUREN. We think.
2. She's 36. That's 17 years younger than Simon Cowell so yes, he is indeed *adopts nana voice* old enough to be her father, tsk tsk etc, etc.
3. She is still technically married to one of Simon's bezzies, property developer Andrew Silverman. But according to Us magazine, the estranged couple have been 'unhappy for some time and a divorce is in the works'. Phew.
4. She's been friends with Mr. Cowell for some time having holidayed with him in St Barts in August last year (along with with hubby Andrew). She also joined Sinitta and Si on holiday in 2011.
5. She's a socialite. You know, like Paris Hilton.
6. She's a dead ringer for Simon's ex fianceé, Mezhgan Hussainy - so much so that even we couldn't initially tell them apart when they all holidayed together last year. Can you? (Mezhgan's in the centre of this pic, Lauren's on the right)
7. Just like Simon, she loves a ciggie, although we're hoping now she's preggers she's kicked the filthy habit.
8. She pretty much knew all there was to know about Simon Cowell before allegedly rubbing belly buttons with him. We know this because she was at the launch party for his *coughs* unauthorised biography, 'Sweet Revenge: The Intimate Life of Simon Cowell' in April 2012.
9. She's not to be confused with Laura Silverman (right) who is the actress sister of US comedian Sarah Silverman (left).