Stephen Amell, Grant Gustin

Well, that didn't take long!

Now that The CW has officially ordered The Flash to series, TVGuide.com can exclusively reveal that the first Arrow-Flash crossover will occur much sooner than fans might've expected: Stephen Amell, who plays Arrow's emerald archer Oliver Queen, appears in The Flash pilot!

The Arrow spin-off stars Grant Gustin as Barry Allen, a scientist who's gifted with the power of super-speed in the aftermath of a freak accident that transforms him into the Fastest Man Alive. Given that Barry originated on Arrow, it seems only fitting for Oliver to return the favor, but there's a twist: The Arrow isn't visiting Barry's hometown of Central City.

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"In the Flash pilot, Barry comes to me," Amell tells TVGuide.com. "[It's a] little snippet in the Flash pilot where he and I share a scene together, it's in his pilot, but [filming] it felt like our show because he's coming to Starling City. That, to me, was one of the most rewarding things that I did as an actor because it was essentially the same crew that we used for our pilot, and it was two years later and it was the same director. It was like going back in time. [Flash and Arrow director] David Nutter asked me to be a part of the pilot and I will never say no to David Nutter."

One can only hope that this early synergy opens up the possibility for many more crossovers to come, especially since the spin-off hails from Arrow's Greg Berlanti and Andrew Kreisberg and DC Chief Geoff Johns. "We'd be insane if we didn't do crossover stuff," Amell adds. "I don't know that it has to be an event or big moments, but the shows share a universe, and not utilizing that fact would be insane. I'm sure that we will at some point."

Are you excited to see Barry and Oliver onscreen together again?

Get your first look at the Flash in action:  

(Full disclosure: TVGuide.com is owned by CBS, one of The CW's parent companies.)