Simon Cowell struggled to know what to do in the months after his son was born, the music mogul has admitted.
In an interview with The Sun on Sunday, the X Factor judge, 56, who is dad to two-year-old Eric, said he did not know what to expect from fatherhood.
He said: "I genuinely didn't know what it was going to be like to be a dad.
"The first seven or eight months dealing with a baby, you just don't know what to do.
"And then suddenly one day everything changes. It's the most incredible thing."
The producer said he sees himself in Eric, who has already been trying to pull "stunts" just like he did as a child.
As well as the X Factor, Simon also juggles America's Got Talent and his music production company Syco, but he said his own father worked long hours and they still managed to have an "incredible relationship".
Insisting that Eric, his son with girlfriend Lauren Silverman, is not spoilt, Simon said he wants to make sure the youngster is polite and has a happy childhood.
In the wide-ranging interview, Simon also praised his fellow X Factor judge Cheryl for overcoming a "stressful" year on the show and said she looked the best he has ever seen her at his recent summer party.
He also said the singer, who is dating One Direction star Liam Payne, 22, would make an "amazing mum".