Later, Charles was spotted walking into Buckingham Palace holding two blue teddy bears.
"Charles looked so happy," a palace insider told Star. "Watching Harry become a father himself will be a very proud moment for Charles."
According to Star, Harry's close bond with nephew Prince George has made him especially excited to welcome a son of his own.
"Harry can't wait to become a dad and he's already got a name picked out," an insider tells.
"Truly, everyone will be thrilled. This is something Harry and Meghan have both dreamed of."
The news is especially exciting for Harry's grandmother, Queen Elizabeth II.
"We haven’t seen the Queen that happy and that excited in a long time – it was wonderful to see," an insider revealed to New Idea earlier this year.
The source went on to say the mood has really continued throughout the palace since they returned. And no-one could be happier."
Royal expert Katie Nicholl revealed that Meghan will make the perfect mother-to-be.
"Meghan is very doting with children. She is very maternal and she was thrilled to meet George and Charlotte. I think one of the lovely things that I discovered [while writing] the book was it was actually a moment involving children when Meghan really fell for Prince Harry," she said.