In the first season of Westworld, secrecy and subterfuge surrounded Jimmi Simpson’s portrayal of young, wide-eyed William. Though the actor guessed that he was meant to be playing a younger version of Ed Harris’s villainous Man in Black—based on, of all things, the way a makeup artist plucked his eyebrows—the subject was not one he was allowed to discuss. Harris, who was also kept in the dark for most of the season, hardly talked to Simpson at all.

But all that changed in Season 2, which meant that Simpson was able to lean on the Oscar-winner for help in shaping his performance. Westworld garnered an impressive 21 Emmy nominations on Thursday morning—just one less than Game of Thrones—with one in the guest-actor category going to Simpson for his multi-episode stint, which spanned over a decade of his character’s life. Simpson hopped on the phone Thursday from a mini-holiday, where he is celebrating his recent engagement to actress Sophia Del Pizzo, to explain how Harris, co-star Evan Rachel Wood, series co-creator and director Lisa Joy, and an unexpected personal loss helped shape his Emmy-nominated turn.

Thanks to both the looping and time-hopping nature of Westworld, Jimmi Simpson’s performance in Season 2 had to both take viewers back before the events of Season 1 and believably blur his portrayal into that of Ed Harris. In one of his episodes, “The Riddle of the Sphinx,” the same scene plays out three times; in two of those scenes, Simpson is playing two variations of William, one younger, one older. In the third, the character has aged into Harris. To help match the older actor’s performance, Simpson was given audio of Harris reading the lines that he could mimic. In the middle scene, he was assisted by some subtle but effective aging prosthetics. As the director of the episode, Lisa Joy, revealed exclusively to Vanity Fair, the show also spliced some of Harris’s audio into Simpson’s vowels during post-production in order to match the tone of the two actors. Simpson said he capped the whole thing off with what he laughingly called “a little jaw acting.”

The repetitive nature of those scenes allowed Simpson to enter into what his co-star Evan Rachel Wood has jokingly called “the acting Olympics.” He had the opportunity to take the same lines of dialogue and imbue them with the pain and toll that the intervening years had taken on William. “It’s like an amazing puzzle that you get to keep playing,” Simpson said. “And it keeps getting interesting each time you play it.”

Plenty of actors have been asked to play younger versions of famous people, but Simpson had the added challenge of needing to work beyond impression in order to make sure his Season 1 version of William—which he created without knowing for certain what his connection with Harris would be—would match the William of Season 2. Adding another complication was the fact that before he filmed his final scenes for Lisa Joy—with an hour’s worth of aging makeup already applied—Simpson discovered that his dog of 16 years was going to have to be put down. Here, he said, is where Joy stepped in.

Thanks to his tears, “I ruined the age makeup,” he said. But Joy assured Simpson that he would be done in time to get home to say goodbye—and, unbeknownst to Simpson, quietly arranged for a specialist she had used herself to come to his house later that day and put his dog down. “It was her huge directing debut, and she had everything at stake, and she was so calm,” Simpson said, still astonished at the memory. The actor channeled all that grief into his performance as an innovator grappling with the disappointing insufficiencies of one of his creations, a robotic host version of Jim Delos played by Peter Mullan. “I took the weight of my own loss that day, and I put it into the machine, and it was there. . . . William’s fucking exhausted,” Simpson said. “Delos has become this albatross.” Simpson made it home in time to say goodbye. “That was because of Lisa. I would have missed it if it had been anyone other than Lisa.”