"Legends of Tomorrow" will likely feature an appearance from Green Arrow, Cisco Ramon and Arsenal, as well as the possible return of Ronnie Raymond in the series.
The "Tomorrow People" star Robbie Amell teased fans of a possible appearance in the DC Television universe as posted a photo of his character's old quantum splicer with the caption "Hello old friend". Amell's "The Flash" co-star Victor Garber also posted a photo of the two reuniting on his Instagram page. Garber will be part of the main cast of "Legends of Tomorrow" as the other haft of Firestorm duo Professor Martin Stein along with Jax Jackson (Franz Drameh).
It was during the season 2 premiere of "The Flash" that Ronnie Raymond (Amell) as Firestorm along with Professor Stein (Garber) try help Barry Allen/The Flash (Grant Gustin) to stop the singularity from destroying Central City and the entire world. Ronnie was able to stop the black hole by exploding it sacrificing himself to save the city leaving both The Flash and Professor Stein the survivors in the event.
Several fans speculated that Ronnie could return in "Legends of Tomorrow" since Garber's photo tagged "Legends Of Tomorrow" and producer Andrew Kreisberg stated that Ronnie could appear in flashbacks or in a certain time period since the spin-off series is about time travel, Bleeding Cool reported.
In other news, several characters from "The Flash" and "Arrow" series will make an appearance in "Legends of Tomorrow".
"Arrow" star Stephen Amell is rumored to appear in the show as the show's cast member Caity Lotz teased that Oliver Queen might sport his classic goatee within the show. Amell quickly dismissed the speculation saying that he is 100 percent sure Oliver will not sport a goatee at all whether it be "Legends of Tomorrow" or "Arrow" TV series.
Former cast member Colton Haynes also teased Roy Harper/Arsenal for "Legends of Tomorrow" as he announce his comeback in the "Arrow" series and teased fans about appearing in the spin-off during a panel in AsiaPop Comic Con several months back.
"The Flash" TV series star Carlos Valdes stated that Cisco Ramon will have an "interesting take" in the series and co-producer Greg Berlanti added that Cisco is not the only character appearing in the show and with time travel involved , everything could happen, Entertainment Weekly reported.
"Legends of Tomorrow" will premiere on Jan. 21, 2016 on the CW Network.