The former "Suits" actress - who was known as Meghan Markle before her marriage to Prince Harry - and her husband have seen Doria Ragland on a number of occasions since they tied the knot in May, as the social worker has been giving them her support in the wake of Meghan's father, Thomas Markle, giving a number of interviews about the couple.
The Duke and Duchess have been invited to visit the Commonwealth Realms of Australia and New Zealand by the countries' respective governments.
The tour will end with four days in New Zealand.
They will also travel to Fiji and Tonga.
The Duke and Duchess will also attend the Invictus Games Sydney during their tour, which takes place between 20 and 27 October.
They arrive in Sydney on October 16, before heading to Dubbo where locals say they are excited to welcome the royal pair.
Prince Harry and Meghan will undertake an official visit to Australia, Fiji, Tonga, and New Zealand.
A source told Stuff earlier in 2018 that they planned to cross the ditch for a royal tour of Aotearoa on about October 28.
The Prince of Wales spent a week with Meghan and Harry at the Castle of Mey.
The city of Suva in Fiji is sure to be another highlight of the royal tour. "Should I campervan? Am I a campervanning girl?", the South Island and Waiheke won her over, inspiring her to write a "love letter to all things Kiwi".
Meghan and Doria have always seemed to be really close and the new Duchess is reportedly having a hard time being so far away from her mom, which is one of the reasons Doria is planning on moving and taking the classes.
The couple will land in Sydney, Australia on October 16, where they will spend nearly a week in the country, before flying to Fiji on October 23 and then to Tonga on October 25.