The final major pieces of the Outlander casting puzzle have finally fallen into place as the time travel drama series has added New Zealand actor Gary Young (The Shannara Chronicles, Crouching Tiger, Hidden Dragon: Sword of Destiny) and relative newcomer Charlie Hiett (Judge John Deed) in the roles of Mr. Willoughby and Captain Thomas Leonard, respectively.
Fans of Diana Gabaldon's series of Big Whopping Books will already know the importance of Mr. Willoughby in the third book's (titled Voyager) storyline, on which Season 3 is based. As for Captain Thomas Leonard, the young British captain plays a key role during Claire (Caitriona Balfe) and Jamie's (Sam Heughan) sea voyage to Jamaica (Fun Fact: That part of the show will be filmed in South Africa, where fellow Starz historical series Black Sails was also filmed).
Here's the official character description for Mr. Willoughby, per Deadline:
A Chinese man with a deep knowledge of Eastern medicine, Mr. Willoughby (Young) is a talented poet in exile with an even deeper love of women. Willoughby, a confidante of Jamie Fraser, speaks English well but hides it when it suits him. He is even more of an outsider than Claire in 18th century Scotland.
Now here's the official description for Captain Thomas Leonard (be aware that this one is a tiny bit more spoilery, though nothing major per se):
Hiett's Leonard is the inexperienced, by-the-book de facto captain of the Artemis. Promoted quickly due to the untimely deaths of his commanding officers, Leonard takes his job very seriously, though it weighs heavily on his young shoulders. A third lieutenant, he never thought he would be the captain of a man-of-war ship. Above all, he wants to do what is right by the British Navy — whether or not it is right by his own personal morals.
There's no premiere date slated for the third season of Outlander just yet, but the show should debut when Black Sails wraps up in early April.