Simon's ex-girlfriend Sinitta appeared to be the first to react to the news that the 'X Factor' boss is alleged to be expecting a baby with his friend's wife, Lauren Silverman, describing it as "half miracle, half nightmare".
Who is Lauren Silverman? Here's everything you need to know about Simon Cowell's alleged baby mama.. in 90 seconds
Take a look at their reactions in the gallery below...
Meanwhile, Simon's mother Julie is reported to have told The Sun she is "delighted" at the "wonderful" news.
However, he is yet to speak about the news, and the office for his Los Angeles lawyer said on Wednesday: "We have no comment."