Jamie's wife Jools Oliver is equally excited about the new arrival and gushed about their newborn boy.
Despite having endured labour not long previously, she took to her own social media account to share the happy news.
She wrote: "Little baby boy Oliver has arrived we are so very happy, blessed, grateful and totally in love all over again and so very proud of our two eldest daughters who cut the cord. Jamie was my hero. (no name yet)!!! XXXX (sic)"
However, with all the excitement, the couple have yet to find a name for the little one and Jamie recently revealed Jools is planning something that is "floral or seasonal".
He said: "Jools is leading the way, very floral, very seasonal, lots of actions of the earth.
"She told me I'm not allowed to talk about it and I don't want to get into trouble because I'm doing so well at home."
And with their three daughters called Poppy, Daisy and Petal, will the couple decide to name their newborn son Rock, Cliff or Glenn to show their fondness of nature and the natural world?
Tagged in Jamie Oliver Jools Oliver