Viewers watched on as Williams seemingly confirmed Arya Stark’s death in the forthcoming final season of the HBO show. However, she swiftly returned to stage confirming the whole thing was a huge April Fools prank.
She made the "accidental slip up" after Fallon pushed her to reveal a small detail about the new episodes. Immediately clasping her hands to her mouth, the actor asked the host whether the show was live or not. Fallon reassured her they could cut the spoiler out, but Williams ran off leaving the audience in silence.
After Fallon followed her backstage, the two swiftly returned – smiles on their faces – to exclaim: “April Fools!”
One character who fans seem concerned about going into season eight is Jon Snow (Kit Harington), thanks to the release of a series of posters.
The way Jon is sat in his one mirrors the pose of Ned Stark (Sean Bean) in the promotional poster for the very first season of Game of Thrones back in 2011, and we all know how things ended for him.
Another theory doing the rounds is that Cersei (Lena Headey) could be the unlikely saviour of Westeros in a battle that could see Bran Stark (Isaac Hempstead-Wright) become the show’s true villain - although Hempstead-Wright himself as rubbished this idea.
You can find a rundown of every character – from worst to best – below.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies