"Doppelganger" is the fifteenth episode of the sixth season, and 130th episode overall of The CW series Arrow. The episode sees the return of former main character Roy Harper (Colton Haynes). It also sees the return of Thea donning her Speedy suit since the ninth episode of the fifth season. The episode stars Stephen Amell (Oliver Queen) who is joined by fellow main cast members David Ramsey (John Diggle), Emily Bett Rickards (Felicity Smoak), Katie Cassidy (Black Siren), Paul Blackthorne (Quentin Lance), Willa Holland (Thea Queen), Echo Kellum (Curtis Holt) and Juliana Harkavy (Dinah Drake). Main cast member Rick Gonzalez (Rene Ramirez) is also credited but does not appear in this episode.