Watch A Clip From The Flash's Debut On 'Arrow'

Thursday marks a pretty momentous occasion in the DC Universe. That's the day the latest episode of Arrow premieres, with the first appearance of a major character in both the TV universe, and maybe the movie universe as well. We're talking about Barry Allen, aka The Flash, who'll have a two episode arc on Arrow starting with Thursday's episode, The Scientist.

Like the grand comic book tradition of "first appearances" though, Allen (played by Grant Gustin) doesn't show up fully formed as The Flash. He's just a scientist investigating a crime. Watch a clip below.

Here's a clip from the next episode of Arrow, via The Hollywood Reporter.

And here's the episode description:

BARRY ALLEN COMES TO STARLING CITY — A seemingly impossible robbery at Queen Consolidated's Applied Sciences Division brings Central City police scientist Barry Allen (guest star Grant Gustin) to town. Citing a similar case back home, Barry offers to help Oliver (Stephen Amell) and team with the investigation. Oliver senses there is more to Barry than meets the eye, but he's distracted by the similarities between this current case and something that happened on the island. Meanwhile, Felicity (Emily Bett Rickards) takes a liking to Barry, which doesn't go unnoticed by Oliver. Sin (guest star Bex Taylor-Klaus) asks Roy (Colton Haynes) for help when a friend of hers goes missing. Roy is surprised when Thea (Willa Holland) not only encourages him to help, but joins the search. Unfortunately, Sin's friend is connected to Brother Blood (guest star Kevin Alejandro), and their search ultimately gets one of them seriously injured.

A few weeks back, it was revealed the strength of the character changed the original plan for him. Allen is still going to be introduced over a two episode Arrow arc but, originally, the 20th episode of the series was going feature him in the red Flash costume. That reveal is now being saved for a full on Flash pilot. How the character's arc will resolve on Arrow is still up in the air.

Are you excited for this iteration of The Flash?