The 26-year-old played Jane Bennet in Pride and Prejudice and Zombies: Dawn of the Dreadfuls.
This regal role will be Luddington's first time in the shoes of a leading lady.
Luddington does have something in common with the princess-to-be - she hails from the British county of Berkshire, the same place Middleton, 29, grew up.
As for researching for the role for the film, which is reportedly in high-gear in order to premiere in time for the April 29 wedding, Luddington's good-to-go, according to her sister.
"Camilla is very excited," People mag quoted her sister as telling Sun.
"She has always followed the Royal Family and never dreamt she'd be playing in a movie about them."
Nico Evers-Swindell, a fellow newcomer, will play Luddington's prince.
