How's her English accent?
The film, directed by Pablo Larraín, charts the end of Diana's marriage to Prince Charles.
The synopsis for the trailer reads: "The marriage of Princess Diana and Prince Charles has long since grown cold.
"Though rumours of affairs and a divorce abound, peace is ordained for the Christmas festivities at the Queen's Sandringham Estate.
"There's eating and drinking, shooting and hunting. Diana knows the game. But this year, things will be a whole lot different.
"Spencer is an imagining of what might have happened during those few fateful days."
Poldark star Jack Farthing plays Prince Charles.
It's a bumper year Diana portrayals, with Elizabeth Debicki taking over the role from Emma Corrin for seasons five and six of The Crown.
You can watch the trailer below or by clicking here.
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