Echo Kellum, who plays Curtis Holt also known as Mr. Terrific on Arrow, tweeted on reading the 100th episode script, which also happens to be one of the crossovers scheduled to happen in the fifth season for the series. The 100th episode will begin filming on September 23rd to October 7th.
Stephen Amell who plays Oliver Queen a few days ago mentioned that they were wrapping up episode 98, so it’s no surprise they’re gearing up for the 100th episode.
— Marc Guggenheim (@mguggenheim) September 19, 2016
That's a wrap on episode 98. I can't actually believe we're about to hit 100. Super lucky.
— Stephen Amell (@StephenAmell) September 14, 2016