Instagram post newest clue for fans speculating Meghan Markle already given birth

Prince Harry and Meghan Markle's Instagram account launched less than a month ago, but it's already at the centre of a conspiracy theory that the pair have already had their baby.

The Duke and Duchess of Sussex's baby was expected to be born in late April or early May, but an Instagram post from Tuesday has some fans believing Meghan has already given birth.

In the post, the pair thanked the public for donating to various organisations in lieu of getting them gifts for the arrival of their first baby.

"Whether a $5 donation, £1000 contribution, offering to volunteer, or spreading the word, you've played your part," it said.

The post was then signed off from "The Duke and Duchess (and Baby Sussex)", which some fans believe is a hint the baby has already been born.

"I'm sure the baby has arrived…love how you two handle things," commented one user, while another said: "Am I the only one who think the baby has been born already?"

But the post isn't the only telling sign.

Meghan's make-up artist Daniel Martin has recently arrived in Windsor, and posted an Instagram story just down the road from the pair's new home at Frogmore Cottage.

After doing her make-up for the royal wedding and attending her baby shower, some fans are questioning if Martin is in town to help the Duchess prepare for her first picture with the newborn.

That image could be how the public is introduced to the new baby as unlike with the Duke and Duchess of Cambridge, Harry and Meghan won't be posing for pictures with the newborn outside Lindo Wing following the birth.

Instead, they are keeping all details of the baby's birth private.

"The Duke and Duchess look forward to sharing the exciting news with everyone once they have had an opportunity to celebrate privately as a new family," a statement said.

That means there could be a significant window between the birth and the announcement. Meghan also hasn't been seen out in public since March 19.

There's also a Kiwi twist.

Prince William will arrive in Auckland on Anzac Day and then head to Christchurch with Prime Minister Jacinda Ardern to meet with the community after the mosque shootings.

Despite announcing the visit at the end of March, the date was only finalised this week.

Some fans have pointed out that it is unlikely the Duke would be away when Meghan gives birth and that the details of the itinerary weren't confirmed until Kensington Palace knew more about the her delivery date.

Prince Charles is also out of the United Kingdom between May 7 and 10.

There's also other evidence, like reports from The Sun that some Windsor Castle staffers were not allowed access to a car park that overlooks the pair's new cottage.

But earlier this week, famed former assistant to the Queen Dickie Arbiter poured cold water on any suggestion Meghan had already given birth.

He said fans need to stop listening to rumour and simply hold their horses.

While the uncertainty continues, royal family fans will likely have their eyes glued to the Instagram account waiting for the announcement.