After splitting with her husband Prince Charles, Diana embarked on an intense romance with the Pakistani doctor (played by Naveen Andrews). "I'm in love with a heart surgeon," she says.
But Khan was bothered by the intense media scrutiny of their relationship. "If I marry you I have to marry the whole world as well," Andrews's character tells her. "It's impossible."
Their relationship fizzled and Diana went on to meet Dodi Al Fayed, who was with her the night she died in a car crash in Paris in 1997.
Diana's exact October opening date is still to be announced.