The streaming service promises “a never-before-seen look at one of the most-discussed couples in history”.
Royal watchers have questioned the timing of the teaser during the Prince and Princess of Wales’ visit to the US for William’s major Earthshot Prize awards ceremony.
Harry has had a long reported rift with his brother William and also spoken of his strained relationship with his father the King.
The monarchy is also currently facing a serious race row, after a royal aide repeatedly quizzed a black charity boss on where she “really came from”.
The royals are also adjusting in the aftermath of the Queen’s death.
It is directed by two-time Academy Award-nominated and Emmy-winning director Liz Garbus.
No date has yet been officially announced for broadcast, although it is rumoured to stream from December 8.