The 54-year-old first-time dad, who welcomed son Eric in February, shared more photos of his pride and joy on Twitter this week.
"Very handsome like his dad," Cowell said.
Very handsome like his dad pic.twitter.com/JTQIgWRDih— Simon Cowell (@SimonCowell) May 5, 2014
Cowell has said he "regrets" the affair, but is delighted to have a child.
"I regret that part," Cowell told the Mirror last month. "But then of course you have a baby and you look at the baby and you kind of go, 'This is what happened from it. ... It is not something I am proud of or wanted to happen in terms of hurting anyone. It just happened."
Mum and Eric. pic.twitter.com/1W4NEqbfGx— Simon Cowell (@SimonCowell) May 5, 2014