Warning: There is a big “El Camino: A Breaking Bad Movie” spoiler ahead.

“Breaking Bad” fans: If you didn’t get around to seeing the “El Camino” sequel as planned over the weekend, you might want to click away now.

Bryan Cranston, who played chemistry teacher and meth dealer Walter White in the original series, spilled to Rolling Stone that he is the top-secret cameo in the two-hour sequel, which dropped in theaters and on Netflix last week.

“Breaking Bad’s” creator recently confirmed that White is indeed dead. But Cranston has revealed that he was the “key cast member” who was shuttled to Albuquerque, New Mexico, for a flashback scene in the film.

Walt’s resurrection offers a return to the “4 Days Out” episode from Season 2. Jesse (Aaron Paul) and a familiarly bespectacled Walt are depicted in conversation in a hotel hallway and at a diner during a time when Cranston’s drug dealer is ready to up his meth output because he believes his lung cancer has left him with months to live.

“It was wonderful,” Cranston tells the magazine of the opportunity to revisit his character, adding that creator Vince Gilligan “wanted to complete the story” by bringing him back for the meetup with Jesse, whose life post-Walt’s demise serves as the heartbeat of the film.

Cranston says returning to the role “felt a little eerie” after six years away, but that it was “in a good way.” He added that it was simple to return to form.

“There are so many talismans I was using on a day-to-day basis during the shooting: his glasses, his shirt, the Wallabees,” he says of Walt’s familiar attire. “I immediately popped back into that character.”

In fact, he was practically giddy about the experience.

“Being in Albuquerque, being around a lot of the same crew, having Aaron there, and Vince, and [producer] Melissa Bernstein, I tweaked a little bit, because it’s like, ‘Oh my god, six years, and we’re back!'” he says.