All The Actors You Probably Forgot Were On 'Downton Abbey'

After six memorable seasons, "Downton Abbey" comes to an end in the U.S. on Sunday night. (The series has already aired its final episode in the U.K.)

How we'll miss Lady Mary constantly acting superior to Lady Edith. How we'll treasure the days when the Dowager Countess of Grantham made us burst out laughing with her witty one-liners. 

But if we think back, we've been missing so many things about the show already, including Lady Sybil, Matthew, William, Ygritte Gwen, and of course, Isis.

Here are all the actors you may have forgotten were on the beloved series:

So long, Downton.