The former Family Fortunes host is expecting a daughter with fiancée Claire Nicholson on April 20. He also has son Philip from his marriage to first wife Lynne.
He told Hello!: "Bringing up a little girl will be a different experience for me. I won't be off chasing my career like I did when Philip was born."
The 53-year-old said the new arrival will be named Grace, Olivia, Amy or Eleanor, but the couple have been unable to make a final choice.
Dennis met life coach Nicholson, 37, when she asked him to dance at a ball in memory of late Holby City star Laura Sadler.
He was previously married to actress Amanda Holden for eight years.