Prince Harry's overseas trip prompts new claims Meghan Markle already had royal baby

There's no word from Windsor about the arrival of a royal baby, but Prince Harry's announcement of a surprise trip to the Netherlands has sparked rumours he's already a dad.

The birth of the Duke and Duchess Sussex's first-born child has been surrounded by secrecy, leaving everyone guessing when and how it will be announced.

On the streets of Windsor, the patriotic royal watchers are patiently waiting.

"I wake up in the middle of the night to see if anything can happen - I wait for the phone to ring if someone's going to tell me," one said.

"I should be able to relax when the baby's here."

And Thursday's announcement Prince Harry's off to the Netherlands next week has some wondering if Baby Sussex is already here.

"Her baby will be the first bi-racial baby in line for the throne, and also an American citizen," another royal watcher said.

The front-runner for a name is Diana, after Harry's late mother.

But, boy or girl, their royal debut won't be on the steps of the Lindo Wing like their royal cousins. Instead, Markle is believed to be following in the footsteps of the Queen with a home delivery.

The announcement is expected in the days - not hours - following the birth. Baby Sussex will become seventh in line to the throne behind Harry.

"Harry will do a lot of the duties - changing nappies, probably changing old-fashioned nappies because that's far more green," Majesty Magazine editor Ingrid Seward said.

"[I] can't see him getting out the pampers because that would be very un-environmental."