Sneak peek into the new life of Meghan Markle, Duchess of Sussex

The Duke and Duchess of Sussex will appear along with Her Majesty, Prince Charles, Prince William, Princess Anne and Sophie, Countess of Wessex, in the UK's ITV show. Photo / Getty Images

A trailer has just landed for a new documentary on the royals that promises to offer a behind-the-scenes glimpse into Meghan Markle's new life as part of the family.

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.

The preview shows Meghan admiring her Givenchy wedding dress and commenting on the silk tulle wedding veil, which featured a flower from all 53 Commonwealth countries.

"Fifty-three countries, oh my goodness," says the 37-year-old in the clip from the documentary, which will include her first interview since becoming a royal. "It'll keep us busy."

The former actress appears to be wearing the same Roland Mouret dress she sported on the day before her wedding to Prince Harry, 33, so it's possible viewers will be treated to candid footage from their big day.

Meghan is joining Harry as a Commonwealth Youth Ambassador as part of her royal duties.

Harry is seen in the documentary joking with visitors that he panics when he stumbles upon the Queen.

Speaking with hospitality workers visiting from the Caribbean, in a scheme set up by the monarch, the prince says: "You guys have spent way more time in Buckingham Palace than I ever have — and you've only been here two weeks.

"Have you bumped into the Queen yet? If you suddenly bump into her in the corridor, don't panic. I know you will. We all do!"

The Duke and Duchess of Sussex will appear along with Her Majesty, Prince Charles, Prince William, Princess Anne and Sophie, Countess of Wessex, in the ITV show.

"The Queen is the most well-travelled monarch in history and it's been fascinating to see how she has passed on her experience to the younger generations of the royal family," said Nicolas Kent, creative director at Oxford Films and executive producer of the documentary.

Meghan Markle became the Duchess of Sussex when she wed Prince Harry. Photo / Getty Images

"With the Duke and Duchess of Sussex about to embark on their first Commonwealth Tour to Australia, New Zealand and the Pacific exactly 65 years after the Queen's first Commonwealth Tour, this series could not be more timely."

The newlyweds are due to arrive in Australia in October, before travelling to New Zealand, Fiji and Tonga.

ITV's Jo Clinton-Davis said: "This film is a rare opportunity to see Her Majesty up close and behind the scenes in this role, which means so much to her and has been so significant for Britain and the Commonwealth."