Announced at the Arrow Panel Saturday night at Comic-Con International in San Diego, Charlie Barnett (Russian Doll) is set to join The CW series' final season as John Diggle, Jr. in a new series regular role.

Diggle, Jr., also known as J.J., is the Flashpoint-born son of John Diggle (David Ramsey) and Lyla Michaels (Audrey Marie Anderson). Fans will meet J.J. in the future as the leader of the Deathstroke Gang, where he faces off against Mia Smoak and his adopted brother, Connor Hawke.

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Before Barry Allen created an alternate universe in Flashpoint, Diggle and Lyla had a young daughter. However, once Flashpoint changed the timeline, Barry discovered Lyla gave birth to a son instead. Arrow's flash-forward to the future revealed Diggle adopted Connor Hawke, leaving fans to wonder what happened to Diggle, Jr.

Barnett stars in the Netflix series Russian Doll and Tales of the City, along with roles in Chicago Fire, Secrets and Lies and Valor. Joining Barnett as new series regulars include Katherine McNamara, Joseph David-Jones and Ben Lewis as Mia Smoak, Connor Hawke and Oliver Queen’s adopted son, William Clayton, respectively.

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Returning Tuesday, October 15 at 9 p.m. ET/PT on the CW, Arrow stars Stephen Amell as Oliver Queen, David Ramsey as John Diggle, Rick Gonzalez as Wild Dog, Juliana Harkavy as Black Canary, Colton Haynes as Arsenal and Katie Cassidy as Black Siren.