Simon's confidante and former partner, Sinitta, seemed to be one of the first people to hear, posting a mysterious tweet two days before the reports surfaced.
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"Something has just happened... half miracle, half nightmare! #WakeMeUpIWantToGetOff!!," she wrote on Twitter.
Although the tweet does not directly mention the X Factor mogul or Lauren's pregnancy, the timing seems to allude to the 53-year-old's impending fatherhood.
Soon after the news broke, fellow Britain's Got Talent judge David Walliams displayed his cheeky sense of humour as he made reference to the baby announcement.
"For the record @SimonCowell and I tried to have a baby together for many years. But I just couldn't get pregnant," he joked, receiving more than 1,500 retweets.
The comedian became a dad to Alfred in May, his first child with model wife Lara Stone.
Fellow judge, Amanda Holden, who is currently on holiday with her children and husband, shared her excitement at the prospect of all four of the Britain's Got Talent judges being parents to young children in time for the next season of BGT.
"I am still here! Just enjoying a family break!! So! All Four Judges with potentially 4 kids under 2 for BGT 2014!!"
Amanda, 42, welcomed her second daughter, Hollie Rose, at the beginning of 2012.
The fourth member of the judging panel, Alesha Dixon, recently announced that she was expecting her first child with dancer boyfriend Azuka Ononye. The singer, 34, is due to give birth in December.