One of the first details director Guillermo Del Toro ever shared about his plans for a sequel to his 2013 "mecha vs. kaiju" film PACIFIC RIM was that the scientists played by Charlie Day and Burn Gorman would be returning as main characters. Things have changed since then, though. Del Toro isn't directing the sequel, PACIFIC RIM: UPRISING, Steven S. DeKnight is, and there's a chance that the script DeKnight is working from is different than the story Del Toro had in mind in 2013 / 2014. (Although Del Toro is still involved with UPRISING as a producer.)
As UPRISING went into production, it was announced that the film would star John Boyega, Scott Eastwood, Cailee Spaerny, Jing Tian, Levi Meaden, Adria Arjona, Ivanna Sahkno, Rahart Adams, Shyrley Rodriguez, Zhang Jin, Wesley Wong, Lily Ji, Chen Zitong, Lan Yingying, Qian Yongchen, Xiao Yang, and Kim Jeong-Hoon. No Day or Gorman.
When an image of an UPRISING call sheet leaked online with Day, Gorman, fellow PACIFIC RIM star Rinko Kikuchi, and Karl Urban listed on it as cast members, the image was quickly removed with no comment from the studio or filmmakers. Urban did deny that he was involved with the film.
Well, since no one else is confirming that he's in PACIFIC RIM: UPRISING, Day has gone ahead and confirmed himself. During an interview with Collider, Day wasn't able to say much about the sequel but did say that DeKnight is taking it in his own direction and the story follows a group of younger characters while he and Burn Gorman are present to help tether the film to the first one. Day's character is back, and according to the actor he's wearing some great clothes.
PACIFIC RIM: UPRISING is scheduled for a February 23, 2018 release. Now that I know for sure that Day is in it, I'm looking forward to it even more.