The two-part Queen of the World examines Elizabeth II's passion for the Commonwealth and how she is passing on the baton to the younger generation.
In the clip, Meghan is shown admiring her Givenchy wedding dress as it is revealed to her for the first time - complete with intricate veil featuring embroidered flowers from all 53 countries of the Commonwealth.
"But just keeping completely relaxed was important", she said in a video published by Country Living magazine. If you suddenly bump into her in the corridor, don't panic. "It will keep us busy", as she admires the incredible embroidery on the dress.
Meghan Markle knows that royal protocol prohibits her from expressing political opinions, but apparently, Prince Harry's friends have picked up on the Duchess of Sussex's "trendy lefty stuff" - and they do not like it.
"Have you bumped into the Queen yet?"
The source told "Entertainment Tonight": "She really is taking the new job part of her role seriously having meetings with Palace staff and learning about the Commonwealth so she can support Harry in his new role as Commonwealth Youth Ambassador".
The Duke of Sussex has joked that he still finds it intimidating to stumble across his 92-year-old grandmother, the Queen, when visiting Buckingham Palace.
Markle's participation includes the support of the Royal Foundation, as well as the name recognition that comes with her face on the cover.
The newlyweds are due to arrive in Australia in October, before travelling to New Zealand, Fiji and Tonga.