The 40-year-old musician took to Instagram to share the first picture of his newborn son with his life partner.
"Incredibly excited to announce the arrival. We're all bursting with love for the newest little member of our family! Feeling very blessed to be daddy to this little man.
"... And the luckiest man in the world to be husband to such a strong, loving and warm-hearted woman and add to my beautiful family #KeatingClan @stormykeating @jackkeating_ @missyykeating @_alikeating #BabyKeating," he wrote.
This is Keating's fourth child - he has three children - Jack (18), Marie (16) and Ali (12) - with first wife Yvonne Connolly, whom he divorced in 2015.