The 54-year-old music mogul welcomed his first child Eric, named after his father, with girlfriend Lauren Silverman last month.
And, speaking in his first television interview since the birth on 14th February, Simon revealed all to ex-girlfriend (and Extra star) Terri Seymour.
He revealed: "I got there [to the birth] with two hours to spare… I held him within five minutes of him being born.
"I actually said to Lauren beforehand, 'What if I like the dogs more than him?' and she said, "You're gonna be absolutely fine," and then literally within seconds of him being born, I got it!"
Heading back to London on Wednesday, it will no doubt be the first time that baby Eric will meet his mother Julie, and brother Tony.
Speaking about his mum, Simon said: "I think she's told the whole village ... she's really excited. I look at him, Eric, and I think of my dad all the time, so it's a really good thing."
Simon also revealed that he is thinking about having more children, saying "I wouldn't rule out [more children]!
"Well, I've got Squiddly and Diddly [his dogs], and I couldn't imagine Squiddly or just Diddly...I had a brother when I was younger, so I kind of think it's cool to have two or three... two."
How exciting! We can't wait to see the Britain's Got Talent boss land in the UK with his baby son and girlfriend.