Flora, who's the granddaughter of the Queen's cousin, Princess Alexandra of Kent, has filmed small scenes with Maggie Smith and Hugh Bonneville according to the Daily Express.
It is hoped that 18-year-old Flora's royal connection will appeal to obsessive royal watchers and fans of the show in the United States.
Even the Duke and Duchess of Cambridge are obsessed with Downton Abbey - we wonder what they think of this new royal link?
A source said, "There's a lot of excitement among the royals and they will almost certainly be watching the new series now.
"Everyone's really proud of Flora for bagging a role in such a big show at such a young age and for doing it off her own back."
Flora is said to have filmed the series while on her gap year. She finished at £30,000-a-year Rugby school last spring, and is set to start at St Andrew's University in September.
Her parents James, who is the Queen's Godson, and Julia met at the university in a similar way to William and Kate.
What do you think?
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