"I'm going to insist the baby is called Jack," he said, referencing 22-year-old Jack Grealish.
"Or Jackie," he hastily added.
The remark came after midfielder Grealish's spectacular 85th-minute score, giving his team Aston Villa the win against Cardiff City.
Prince William, already father to Prince George, 4, and Princess Charlotte, 2, is expecting his third child with Kate Middleton in the coming weeks. In preparation, media barriers have been installed outside St Mary's Hospital in London.
Bets are already being placed on what the couple will name their baby, with bookmakers' top picks for boy's names being Arthur, Edward and Albert.
Among the top bets for girl's names are Alice, Mary, Elizabeth and Victoria.
Jack is not among the top bets.