If Maisie Williams doesn't get awards for her acting on Game of Thrones' final season, she just might for her performance on Monday night's episode of The Tonight Show Starring Jimmy Fallon.
The 21-year-old actress pulled off maybe the greatest April Fools' prank ever when she appeared to accidentally share a GoT spoiler on the talk show. As she joked to ET's Leanne Aguilera at the HBO series' press day in New York on Tuesday, she was so impressed by her own acting that she started to "convince" herself it was all real.
"It was actually Fallon that came up with it -- it was the show," Williams explained. "We did a little rehearsal of it, and then people were like, 'Wow, it was really convincing because your hands were shaking.'"
"Yeah, your hands were shaking!" Sophie Turner interjected, praising her onscreen sister's performance.
On Monday's Tonight Show, Williams "revealed" that her character, Arya, dies in the second episode of the upcoming eighth season. She couldn't keep her hands still as she started tearing up, asked Fallon if he could edit out her statement and then later ran off stage.
"I just full-on have, like, really bad anxiety, so I always held my hands [together], or I'd move them, because you can see that they shake," Williams told ET of how she was able to pull off the prank so well. "It was just, like, perfect that I would hold my hands up and they started shaking, and I was like 'Oh girl, you're convincing yourself!'"
On Tuesday, the actress made sure fans knew they wouldn't be getting any spoilers from her. "I was one of the last people to wrap, which isn't a spoiler," she hilariously insisted, before dishing on how she prepared to say goodbye to Arya Stark.
"I was, like, so in denial," Williams expressed. "It was the last day [of shooting], I did my scene last. I was really putting it off because I watched so many people wrap and cry, I had to, like, stay out of that emotion, because there were some really difficult scenes to do."
"I wrapped and I was emotional, but I really did feel numb. That's when my numbness came, and then it wasn't until, like, a week later, when you're just doing something and you drop a spoon. I was like 'Ahhhhhhh!' like overreacting entirely, and I just felt like an insane person," she shared.
Turner also said she felt "numb." "I was just numb when I read my last page because it's just so sad," she revealed. "It's so sad that that is the last time I'm reading my character. I just had to go on a long long walk."
"You can start to get yourself so down on being like, 'This is the last time I'm going to read scripts, this is the last time I'm going to be in this location,'" Williams shared. "I got to a point where I had to stop doing them because I was just gonna have a nervous breakdown."
Afterward, the actress said, "You have to snap so that you can slowly start to heal."
Game of Thrones returns April 14 on HBO. See more in the video below.