UPDATE: CW recently confirmed the Flash-Arrow crossover will start on Episode 8, Season 3 of Arrow.
CW's Arrow Season 3 will see a crossover from its upcoming spinoff The Flash, according to a high-level executive from the network.
"It's really going to be an adventure with the Arrow and Flash on both episodes," Arrow executive producer Andrew Kreisberg said to EW on Tuesday. "Watching the two teams come together and fight alongside each other, it's one of the most fun parts."
So, both The Arrow and The Flash will be seeing crossovers by actors Stephen Amell and Grant Gustin.
In May, CW released the extended trailer for The Flash that shows Oliver Queen (Stephen Amell) meeting Barry on the rooftop of an unknown location. "Take your own advice. Wear a mask," Oliver admonishes before somersaulting over the side of the building.
Arrow Season 3 will premiere on Wednesday, Oct. 8 at 8pm ET.
Origins of the Flash
Before he becomes The Flash, Barry Allen (Grant Gustin) appeared in two episodes of Arrow Season 2. The geeky lab assistant comes to Starling City to investigate a mysterious theft at Queen Consolidated. Allen works for the Central City CSI, but takes time away from the office to investigate the unusual crime.
Upon returning to the Central City lab, Barry is electrocuted in a freakish storm caused by the malfunctioning S.T.A.R. Labs particle accelerator. The force knocks Barry into a shelf of chemicals, which his body absorbs as he falls into a coma.
The Flash trailer shows Barry awakening from his coma nine months later. Based on DC Comics lore, the character will soon realize that he possesses the superhuman ability of speed. CW recently announced that The Flash will debut on Tuesday, Oct. 7 at 9pm ET.
It is uncertain whether Felicity Smoak (Emily Bett Rickards) will continue being Barry's love interest as implied in Arrow Season 2. Felicity continues visiting Barry in the hospital until events in Starling City puts a stop to her activities. After Barry is moved to S.T.A.R. labs, his friend Iris West begins seeing him often. In the original DC Comics universe that inspired the series, Barry eventually marries Iris. Iris will be played by Candice Patton in the upcoming Flash pilot.
Two weeks ago, TV Guide's Natalie Abrams tweeted that Oliver - also known as The Green Arrow - will start dating Felicity in Season Three. Naturally, this information will only be confirmed when Arrow Season 3 debuts.
'The Flash' Extended Trailer