TV Article Stephen Colbert on Rick and Morty: Voices an alien in exclusive clip By Clark Collis Clark Collis Senior Writer EW's editorial guidelines Published on August 26, 2015 05:08PM EDT Photo: Adult Swim On Sunday's episode of Rick and Morty, Stephen Colbert finally gets to play someone as intelligent as his blowhard character on The Colbert Report believed himself to be. Specifically, the Late Show host-in-waiting portrays Zeep Xanflorp, an alien with grey matter (or whatever substance makes up his brain) on a level with that of mad scientist Rick. "They're pretty equally matched," says Justin Roiland, who voices both of the sci-fi sitcom's titular characters and co-created the show with Dan Harmon. "It's interesting to watch Rick be insecure and s–tty about the fact that he knows this guy is pretty f—ing smart." Rick and Morty airs Sundays at 11:30 p.m ET on Adult Swim. Adult Swim Related content: Rick and Morty renewed for season 3 Rick and Morty: A beginner's episode guide Rick and Morty creators tease season 3 story lines for Beth, Summer WANT MORE EW? Subscribe now to keep up with the latest in movies, television and music.