If you missed the Westworld finale Sunday night, then now is as good a time as any to let you know that the following article most certainly contains spoilers. Specifically, we're going to be discussing (again: SPOILER ALERT!) William's big Man in Black reveal and how star Jimmy Simpson accidentally figured the whole thing out, like, seven months too early.

The twist, predicted by more than a few Reddit users, first revealed itself to Simpson thanks to a seemingly innocuous eyebrow inquiry. "I was with an amazing makeup artist, Christian, and he was looking at my face too much," Simpson told Vanity Fair Monday. "He had me in his chair, and he was just looking at my face, and then he said something about my eyebrows. 'Would you be cool if we just took a couple hairs out of your eyebrows, made them not quite as arched?'"

This eyebrow inquiry was a little too specific for Simpson to just brush off, so he started theorizing. "There's only one that really fit my look and dialect," Simpson recalled. "They didn't reveal any of that to any of us until about [episode] eight, nine, or ten officially. This was probably seven months before I was supposed to know this, but I just said to [co-creator Lisa Joy], 'Am I supposed to be Ed Harris?' She just froze and said, 'I can't say anything, but I will say you have a hell of an arc this season.'"

But instead of flaunting his discovery with the rest of the cast, Simpson had to keep it a secret the whole damn time. "I didn't discuss it with a single person," Simpson said. "Not a single person."

Following that mindfuck of a series finale, we'll have to wait a little longer than expected for new Westworld. HBO renewed the series for a second season last month, but with a catch: no new shit until 2018.