Stewart interviewed the Egyptian political satirist on his show earlier this year after Youssef was arrested by Egyptian authorities for "denigrating Islam" and criticizing Egypt's president, Mohamed Morsi.
Stewart, sporting a short beard, was brought onto Youssef's "The Program" as a prisoner marching to "The Final Duel" from "Star Wars." He even practiced some Arabic for the audience.
Prachi Gupta is an Assistant News Editor for Salon, focusing on pop culture. Follow her on Twitter at @prachigu or email her at email@example.com.