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.
Cowell became a father after a scandalous affair with New York socialite Lauren Silverman, now the ex-wife of his former best friend, Andrew Silverman.
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