The Duke Sussex and the Duchess will share the months with Kills along with Wills and Kate.
Harry, 34, and Meghan, 37, went from London to Windsor in Frogmore Cottage this year.
Earlier on Sunday, Mail was told that they had been developed among two couples, Meghan and Kate were said to be "very different people."
But at Kensington Palace, Sussex said that they continued to be the first baby in the spring.
Harry means "the royal life to escape from the goldfish bowl" before becoming a father.
One source said: "Harry does not want to take her as a husband in a spectacular way.
"It attracts attention to any Kensington garden travel, as it is understood by the public or photographer occasionally.
"Cambridges has a garden on the back, nice, but there is no other place to play.
"Frogmore, within the Windsor security site [where the main house is only open to the public for a couple of days a year] Is isolated, peaceful, quiet and, most importantly, private.
"No one will be coming or going."
They live in the Nottingham Cottage at Harry and Meghan Palace, the former Kate and William residence.
Cambridges now live on a pad of 20 feet for the same reasons.
The multi-million-pound exchange of Frogmore Cottage will be financed by UK taxpayers.
The reform transforms a farmhouse with tens of thousands to Harry and Meghan babyhood.
Forgmore Cottage, in Windsor Real Estate, gave them Queen.
XIX. Century farm today has been rented for royal workers.
But qualification II. The building fails, and before the Harry and Meghan movement there are secret secrets to the City Hall's planning.
It has long been the popular bolthole for Windsors and Queen and others use private and real engagements.