In it, Naomi can be seen portraying the Princess of Wales in a series of snapshots of her life, including the famous minefield visit in Angola.
The trailer opens with a shot of Diana standing alone in an exquisitely decorated room, then shows the royal meeting and greeting awaiting crowds.
It charts the media's obsession with her with a few shots of Diana trying to escape the photographers.
Naomi has Diana's signature blonde crop and big blue eyes down pat, even if her British accent isn't quite as plummy as the original.
Also starring in the film are Lost's Naveen Andrews, who plays Diana's love interest Dr Hasnat Khan, and Douglas Hodge as personal butler Paul Burrell. Cas Anvar takes up the role of Dodi Fayed.
Diana is due to hit cinemas on September 20th.