Decades ago, English actor Tom Wilkinson visited Kenwood House in London and among some Rembrandts, saw a painting of two young aristocratic women - one black, one white.
He didn't think of it again until some thirty or forty years later, when he discovered it was the inspiration behind his new film Belle.
Not only that but the house he had visited once belonged to his character Lord Mansfield.
"It's just up from where I live," Wilkinson says of Kenwood House.
"And I remember seeing the painting there, because there's a small art gallery there and it's got some nice Rembrandts in it and it had this one in it."
The 1779 portrait of Dido Elizabeth Belle and Lady Elizabeth Murray is by an unknown artist, although its widely attributed to Germany's Johann Zoffany, the painter celebrated in the Gilbert and Sullivan opera The Pirates of Penzance.
It depicts two beautifully dressed young women - Dido (played in the film by Gugu Mbatha-Raw) and her cousin Elizabeth (Sarah Gadon) - looking out at the viewer.
The filmmakers went on to learn that both of the girls were adopted by their great-uncle Lord Mansfield, who was also a Lord Chief Justice, and from there the film Belle grew.
"I thought it was just a fantastically interesting story," Wilkinson says.
"What's interesting is the way in which that girl, who was of mixed race was accepted by the family and becomes an integral part of it.
"And how difficult it must have been at that period to accept it."
In the film, directed by Amma Asante, Dido is found by her father (Matthew Goode), a Royal Navy Captain, and taken to live with Wilkinson's Lord Mansfield.
It's here at Kenwood House that she grows up along with her great-uncle's wife Lady Mansfield (played by Emily Watson), his sister Lady Mary Murray (Penelope Wilton) and his other great-niece Elizabeth.
She's raised with equality and privilege, unheard of for a black girl in England in the 18th century. As Dido reaches her late teens and inherits a sum of money, she must battle the social prejudice of the time for self acceptance and the chance at love - all against the backdrop of a controversial slavery case Lord Mansfield is presiding over in the Supreme Court.
The casting of both his onscreen wife and sister meant Wilkinson was reunited with his co-star from Separate Lies, Emily Watson, and Penelope Wilton from The Best Exotic Marigold Hotel.
"Certainly Emily I've done at least four things with her now," he says, adding, "it's always nice to work with friends."
Over Wilkinson's career, he's been in a number of period pieces, from Shakespeare in Love to Girl with a Pearl Earring.
"(But) it doesn't make any difference to me, apart from the clothes you put on," he says.
"A story's, a story's, a story and you enjoy telling it.
"That's what I've done all my life, whether it's The Full Monty or Shakespeare, it's an interesting story and it's worth telling to people."
* Belle opens in Australian cinemas on May 8.
