I just happened to be home these past two Mondays for the LIVE CHATS with two Downtown Abbey cast members. Today was Edith~~ Laura Carmichael.
Here is the word she used when asked about getting the part:
I was gobsmacked to find it was a principle character. It was a very exciting time.
gobsmacked [ˈgɒbˌsmækt]adj Brit slang astounded; astonished
You might hear it come out of my mouth.
By the way, snow in England!