Granada is producing the drama, titled 'Whatever Love Means', and is to begin casting in May. The phrase was uttered by Charles when he was asked by the media after the announcement of his engagement to Diana if he was in love with her.
The scriptwriter is William Humble, who has written dramas about comedian Tony Hancock, and 'Virtuoso', about the pianist John Ogden.
Damien Timmer, Granada's head of drama, said that the film would be a "sensitive portrayal" of Charles and Camilla's love and friendship prior to his meeting and marrying Diana.
Timmer said: "As a nation, we know very little about the early days of Charles and Camilla's love affair."
The couple married on Saturday in a ceremony at the Guildhall in Windsor, followed by a blessing in Windsor Castle, conducted by the Archibishop of Canterbury, Dr Rowan Williams.
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