Celebrities are notorious for hiding away from breaking reports of personal stories, but the music mogul went about his way as normal today.
In fact, the suave X Factor USA judge appeared to be whistling to himself as he left the studios in LA following filming for the new series.
Yesterday, it was reported by American magazine Us Weekly that the 53-year-old is to father a child with New York socialite Lauren Silverman, 36.
The publication has also stated that the mum-to-be is reportedly the wife of SiCo's pal, property mogul Andrew Silverman.
It is thought the couple are now seperated, with Mr Silverman filing for divorce.
Simon, Lauren and Andrew were previously photographed together on a luxury yacht, during a holiday last year.
Celeb pal David Walliams appeared to confirm the news yesterday, writing on Twitter: "Oh yeah, and @SimonCowell is doing a baby with a lady."
Although the comic later joked about his fellow Britain's Got Talent judge: "For the record @SimonCowell and I tried to have a baby together for many years. But I just couldn't get pregnant."
Lauren has been pictured with Simon on various occasions, including a theatre visit in March to see Agatha Christie's The Mousetrap in London, when the pair were photographed smoking cigarettes and giggling together in the back of their car.
The 36-year-old brunette has also holidayed with Simon on his private boat, pictured back in January 2012 smiling and sipping drinks on deck while admiring the views in St Barts.
An array of catwalk-worthy females have previously tried to win Simon's heart, and he even came close to tying the knot.
The lady who came closest was make-up artist Mezhgan Hussainy, whom he proposed to back in February 2010, before the couple went their separate ways last year.
Simon - who has also been linked to Dannii Minogue and Carmen Electra - later admitted it had been "a big mistake".
Over the years, Simon has fiercely rejected the idea of starting a brood, saying in 2009: "God, no. I couldn't have children.
"If I had them here drawing on the walls I'd go nuts. With kids, you've got a routine you can't escape from. You've got to be up at a certain time. Got to listen.
"When all you want to do is sit in a corner thinking."
Yet during a later interview in April this year, he appeared to have softened: "I do really, really like kids, because I can talk to them and listen to them.
"The problem has always been how much time you need to devote to bringing up kids.
"I've always dedicated all my life to work, and at 52, I've probably missed the opportunity."
Daily Star Online are awaiting comment from Simon's US representatives.
UK reps revealed: "Max (Clifford) has spoken with Simon today. This is a very sensitive issue."