The network announced in a tweet Thursday that actor Charlie Field and actress Tiffany Smith will play the duke and duchess of Sussex in the new film.
Field played Carl Von Weizsacker in an episode of Genius and recently appeared as John Craven in Poldark. Smith portrayed Ophelia Avila on Supernatural and previously appeared on Jane the Virgin.
"Let us introduce you to the royal couple! @TiffanyTweets and @CharlieREField will star in Harry & Meghan: #BecomingRoyal!" Lifetime wrote.
Smith celebrated the news in a post on her own account.
"So excited to share this royally awesome news... and to share this adventure with you sir, @CharlieREfield! #BecomingRoyal @lifetimetv," the actress wrote.
Deadline said Becoming Royal will begin filming this month in Vancouver, B.C., and debut on Lifetime in the spring. The movie depicts Harry and Markle's first year of marriage.
Becoming Royal is a sequel to the Lifetime movie Harry & Meghan: A Royal Romance, which debuted in May ahead of Harry and Markle's wedding. The film starred Burgess Abernethy and Parisa Fitz-Henley as Harry and Markle.