Posting a picture of himself next to the late actor via Instagram on July 25, Colfer, 23, wrote: "I'll never forget all the laughs we shared or the faces we made after awkward interview questions…love and miss you, buddy."
The actor is the latest Glee star to honor Monteith after authorities revealed the Canadian-born celeb had died from a lethal dose of heroin and alcohol in his Vancouver hotel room. (Colfer and Monteith had starred in the FOX TV series since its premiere in 2009; their characters, once enemies, later became stepbrothers.)
On July 20, Ryan Murphy, co-creator of Glee, opened up to TV Line about hard the tragedy has been, especially for Lea Michele, Monteith's real-life girlfriend.
"It’s just a crazy, really difficult, very emotional time," he said. "I think what we’re really trying to do is deal with it as a family, which is what that group of people is."
Fox pushed the season five premiere date to Sept. 26 from its original Sept. 19 air date, and Murphy revealed that the show will address Monteith's character, Finn Hudson's death, in the season's third episode.
Michele, 26, is taking the tragic loss the hardest, according to sources. "She's not doing great," an insider recently told Us Weekly. "She's totally devastated."