The eccentric 56-year-old singer's girlfriend, Lydia Longville, 21, gave birth to Leon Wagner Fiuza-Carrilho early this morning.
Proud mum Lydia told her Twitter followers that the little boy was just like his dad!
The couple, who have been together for two years, first met after Wagner performed at The River Rooms in Stourbridge following his stint on the X Factor.
Despite their 36-year age gap, they fell in love and announced they were expecting a baby boy in the summer.
At the time, Wagner said that he did not feel his age.
"If people say I'm a cradle-snatcher, they're short-sighted, I don't feel 56," he said. "To be frank, we love each other very much and can't wait to start a family.
"We'd stopped using contraception so it was inevitable, because she's young and fertile. I'm like a vampire - I only like young blood."
Wagner already has a five-year-old with a former girlfriend, but is said to be 'estranged' from the child - something he says 'breaks his heart'.
Wagner and Lydia said they had picked Leon as it means lion in Spanish, so he would be their 'little lion Wagner'.
More on Parentdish: Older celebrity dads
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