"how am feeling after that episode. not today bby," the young actress captioned the pic.
On Monday, the actress, 23, posted a hilarious video of her best friend and co-star, Sophie Turner, who plays Sansa Stark on the series, messing around behind-the-scenes.
In the clip, a very-bundled up Turner is seen rapping the lyrics to Soulja Boy's 2007 hit "Crank That (Soulja Boy)" while she dances on the top of the fictional Winterfell castle, which is filmed in Belfast, Ireland. Williams' giggles are heard in the background as Turner proceeded to punch a snowball off the building. Turner topped it all off with a dab of course.
"how am feeling after that episode. not today bby," Williams captioned the post.
During Sunday night's insane episode of the HBO drama series, Arya was the ultimate MVP when she killed the Night King with a Valyrian steel dagger (and thus eradicated the entire undead army).
Before Arya left the castle to destroy the Night King, the Red Priestess, Melisandre (Carice van Houten) reminded her of a conversation Arya had with her dancing master, Syrio Forel, back in Season 1 when she recited, "What do we say to the God of Death?" Arya replied, "Not today."
In the same post, Williams also shared a funny photo of the Night King, played by Vladimir Furdik, striking a pose on set. Like fans, celebrities seemed to love the post as many reacted in the comments.
"Game of Thrones" star, Alfie Allen, who starred as Theon Greyjoy on the series (R.I.P), commented, "VLAD." Model Emily Ratajkowski wrote she was "Deceased AF." Comedian Ali Wong simply commented with a crown emoji. Even DJ Steve Aoki chimed in.
However, HBO's official Instagram account said it best: "Oh I'm absolutely ready for a GoT Soulja boy mashup." With only three episodes left of the series (tear) this seems unlikely, however, we can still dream, right?
"Game of Thrones" airs Sundays at 9 p.m. ET on HBO.