Watch: YouTube pranksters 'prove royal experts lie' about Harry and Meghan

A pair of YouTube pranksters appeared to have caught royal commentators lying about having seen Prince Harry and Meghan Markle's Oprah interview.

YouTubers Josh Pieters and Archie Manners, who have nearly 1.5 million subscribers on their channel, convinced four royal commentators to give their opinion on the interview before it had gone to air.

Among those duped by the pair were royal commentators Richard Fitzwilliams and Victoria Arbiter, as well as the Queen's former press secretary Dickie Arbiter and the editor of Majesty magazine Ingrid Seward.

All were paid to give their thoughts, with Pieters and Manners telling them they would be published after the interview was broadcast.

"In the interview, to my mind, this was an actress giving one of her great performances. From start to finish, Meghan was acting," Majesty magazine's Seward says in the video, which was posted to YouTube on Saturday.

"Oprah Winfrey gave them an easy ride. She was totally sympathetic, and there was a great deal in it that the palace will find deeply concerning," royal commentator Fitzwilliams said.

Oprah's interview with Meghan and Harry will air first in the United States today, at 2pm NZ time.

British audiences will wake up tomorrow to headlines and social media posts about Winfrey’s special, but won’t be able to see the full interview until the evening when it airs on ITV.