'Game of Thrones' Star Lena Headey -- Red Wedding was a 'Beautiful Episode'

There were a lot of reactions to this weekend's episode of "Game of Thrones" ... shocking, violent, traumatizing ... but the chick who plays Queen Cersei tells TMZ the ep was nothing short of "beautiful."

Looking less like a sociopathic power-hungry killer ... and more like an overalls-wearing hipster, Lena Headey hit up The Grove in L.A. yesterday when we talked about Sunday's infamous "red wedding."

Headey didn't seem bothered by the fact the throat-cutting wasn't as realistic as it could've been ... instead she praised the show as a thing of beauty.

Word is ... something HUUUGE is gonna happen in the next episode -- so don't be that person who whines about spoilers the next day ... and get caught up!!!