The Safe Haven actor and his wife announced last week that they will be having their first child together later in the year.
Duhamel has since admitted to finding Fergie's initial reaction to her pregnancy quite humorous.
"She was the one when we first found out that was like, 'This s**t just got real'," he disclosed to PageSix, adding: "Those were the first words out of her mouth."
The star went on to suggest that his and Fergie's first child is coming at the perfect time in their lives.
"I'm not 24, I've got some life experience that I think I can impart," Duhamel said. "My mother was the disciplinarian and my father was more of a free spirit. Hopefully I'm somewhere in between."
Duhamel previously suggested that he will be a good father because he has always had a natural rapport with children.
Fergie and Duhamel married four years ago.
Watch a trailer for Safe Haven below: