The Coronation Street star's wife Samantha gave birth to a daughter Sophia Melody. The tot weighted in at 7lb 7oz.
The couple already have a daughter Olivia who is seven.
John - whose character, children's entertainer Jesse Chadwick, has just been dumped by Eileen Grimshaw in the soap - was present at the birth.
The actor, also known for starring in Cold Feet and The Fast Show said: "All three of us - Sam, Olivia and I - are absolutely made up."