Fox has released these official images of Colossus in DEADPOOL. Fox also officially revealed (via EW) that actor Stefan Kapicic is voicing, as well as did some motion capture work for, the mutant.
Kapicic had the following to say regarding his role as Colossus.
"[Director] Tim Miller’s idea of Colossus was to be bigger and stronger than everyone else. So for the motion capture they needed an extremely tall man. I’m 6-foot-4, but he wanted Colossus to be over 7 feet, so they used a stunt double to recreate his height, and he did very good job there. Tim also wanted Colossus to sound as close as possible to the comic book character’s background, so he had me to come in, since my voice was what he envisioned for Colossus, who has an authentic Russian accent. My character’s voice gives him the past history as Piotr Rasputin once you hear him speak. This made him the most authentic to the original idea of the comic book character."
DEADPOOL releases on February 12, 2016.