Adding their voices to the months-long chorus, "Game of Thrones" showrunners David Benioff and D.B. Weiss insist that Jon Snow is really dead. But how can fans know for sure? The answer lies in his eyes

"If you look at his eyes there [in the Season 5 finale]," Benioff tells Variety, "we spent a lot of time --"

"We spent good money on this," Weiss interjects.

"-- to make sure those pupils ... dilate," Benioff continues.

Wait, what? "Your pupillary muscles relax when your body gives up --," Weiss explains, only to be interrupted by Benioff with, "Like your sphincter."

"It is called a pupillary sphincter, as a matter of fact," Weiss continues. "We looked this up on the Internets, and it said your pupillary sphincter relaxes and your eyes dilate, so if you look carefully, Jon's eye dilates."

"Game of Thrones" returns Sunday at 9 p.m. ET/PT on HBO.