The 'X Factor' boss looked every bit the doting dad as he carried little Eric - named after Simon's late father - in his car seat past the waiting paps, who were quick to snap him dropping the baby's blanket.
Simon and his girlfriend Lauren Silverman were seen leaving the Lenox Hill Hospital in New York and then arriving at the St Regis Hotel.
"The last three days have been incredible. Eric, Lauren, sqiddly and diddly all happy," wrote the music mogul on Twitter, referring to his new family and pet dogs.
The last three days have been incredible. Eric Lauren sqiddly and diddly all happy.— Simon Cowell (@SimonCowell) February 17, 2014
Eric was born on Valentine's Day after Simon left the 'Britain’s Got Talent' auditions in London and jetted to the Big Apple to be at Lauren's side for the birth.
He has since treated his fans to some intimate and unusually heart warming snaps of him and baby Eric via Twitter.
"I never knew how much love and pride I would feel," he captioned one pic.
I never knew how much love and pride I would feel. pic.twitter.com/bjwhJvrFBd— Simon Cowell (@SimonCowell) February 16, 2014
Quick off the mark, Simon's baby has already had a song dedicated to him on YouTube...