Stephen Colbert showed his love for Broadway, and his skill at musical comedy, by appearing in a concert version of Stephen Sondheim’s Company – at the composer’s request. Tonight, in character as his conservative blowhard, he plays host to one of the most talented performers in Broadway history: Audra McDonald, who’s just been nominated for a sixth Tony Award, for Best Performance by a Leading Actress in a Play, for her harrowing, haunting impersonation of Billie Holiday