Simon's partner Lauren Silverman gave birth yesterday, and the couple have named their newborn son Eric after Simon's late father.
Baby Eric weighed 6lbs 7oz when he arrived at 10.45pm UK time (5.45pm in New York) at Lenox Hill Hospital, NYC, two weeks earlier than Lauren's expected due date of February 28.
Simon, 54, is said to have been beside Lauren's side throughout.
After spending precious moments with his son, Simon took to Twitter to share the good news with his followers.
He tweeted: "Very happy to say Eric was born at 17.45pm. Healthy and handsome.
"Lauren in great shape. Thanks for all of your kind messages.
"Named after my dad."
Yesterday, Simon boarded a plane to the US for the birth and missed Britain's Got Talent's London auditions.
Earlier in the week he had said: "I am keeping my phone on during auditions 100 per cent. If it happens I have to go and dash on a plane."
The baby is Simon's first child and 36-year-old Lauren's second, who already has an eight-year-old son, Adam, with her ex-husband Andrew.
Huge congratulations to Simon and Lauren on their new arrival!
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