"He's got very strong plans about what he's going to be doing and where he's going to be going," the BGT presenter said. "And I keep saying that's not going to work out because babies aren't as portable as you think in the beginning."
Amanda revealed that she's been advising Simon to: "Just be prepared for how much he's going to love the baby," as she thinks the emotion will "knock him for six."
However, despite her concerns, Amanda believes Simon will be an 'amazing dad' based on how he interacts with children on BGT - she says he speaks to them like adults and is the least patronising of all the judges.
Watch the video above to hear more of Amanda's thoughts on Simon, and some of her highlights from this year's BGT so far - including the moment David Walliams saved Simon's life!
More on Parentdish
Suggested For You
SUBSCRIBE AND FOLLOW
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements.Learn more