Tonight's episode of Arrow saw Grant Gustin become The Flash as the accident occurred that gives Barry Allen the Speed Force!
Grant Gustin appeared for a second time on Arrow helping out Oliver Queen.
Barry Allen also helped Ollie become the hero that everyone knows by recommending and providing the Green Arrow mask!
Below you can check out video from tonight's episode of Arrow featuring the birth of Barry Allen as The Flash!
Arrow returns January 15th at 8pm ET on the CW with "Blast Radius."
It's been rumored that the next appearance of Grant Gustin will be in full costume in his own spin-off series for The Flash as well. A premiere date has yet to be announced, but most likely The Flash series will debut next Fall is our guess.