Special Guest Stars Grant Gustin as Barry Allen / The Flash Stephen Amell as Oliver Queen / Green Arrow Carlos Valdés as Cisco Ramon / Vibe Caity Lotz as Sara Lance / White Canary Danielle Panabaker as Caitlin Snow / Killer Frost Emily Bett Rickards as Felicity Smoak Victor Garber as Dr. Martin Stein / Firestorm Stephen Amell as Oliver Queen (Earth-X) / Dark Arrow Jesse L. Martin as Joe West Dominic Purcell as Mick Rory / Heat Wave Candice Patton as Iris West Tom Cavanagh as Harrison Wells Tom Cavanagh as Eobard Thawne / Reverse-Flash Jessica Parker Kennedy as Wedding Caterer Keiynan Lonsdale as Wally West / Kid Flash Franz Drameh as Jefferson "Jax" Jackson / Firestorm Guest Stars Patrick Sabongui as Captain David Singh Isabella Hofmann as Clarissa Stein Danielle Nicolet as DA Cecile Horton William Katt as Minister Christina Brucato as Lily Stein Co Starring Mackenzie Gray as Greggor Anthony Ames as Angry Boss Paul Herbert as Scientist Jeremy Schuetze as Rob Chris Walters as Norman Guard Robyn Bradley as Wedding Planner Jay MacDougald as Guard Andrea Pizarro as Manicurist Uncredited Melissa Benoist as Kara Zor-El (Earth-X) / Overgirl Mehcad Brooks as Guardian (Earth-X)
