5 Things To Know About Grant Gustin, Stephen Amell's 'The Flash' & 'Arrow' Crossover Event On CW! [WATCH]

Viewers are just a couple hours away from the highly anticipated DC Comics crossover event on the CW network. Though their alter-egos, Grant Gustin (Barry Allen), Stephen Amell (Oliver Queen) will jump back and forth between each other's superhero TV shows on, The Flash and Arrow.

Crossovers aren't new to comics, even to television. On the Batman '66 series, the caped crusaders had to reluctantly team-up with The Green Hornet and his sidekick Kato (featuring a young Bruce Lee). Even the Avengers: Age of Ultron director Joss Whedon had his fan-favorite TV series Buffy The Vampire Slayer and Angel crossover.

Here are five things viewers should know before the crossover event:

1) Super Speed

In our previous recap, we witnessed the origin story of how Barry (Gustin) gained his powers. Due to a particle accelerator explosion at S.T.A.R. Labs, lightning struck Barry and threw him into a vat of chemicals. Though Ollie dealt with a super strong Deathstroke during Season 2, he has never dealt with these metahumans before.

2) Felicity

Making her first guest appearance this season, Barry needed help from Felicity Smoak (Emily Bett Rickards) and the rest of his team when Captain Cold (Wentworth Miller) showed up. Now Felicity is back again, caught in the middle of our two leading men who she cares so much about. Will Ray Palmer (Brandon Routh) show up to make things even more awkward?

3) They Always Have To Fight Before Working Together

It's not a crossover until our superheroes duke it out first. Remember DC Comics and Marvel Comics worked together on their versus scenarios. Everyone wanted to know if the Flash was faster than Quicksilver and if Superman was stronger than the Hulk.

4) Boomerang

In Part One, entitled The Flash vs. Arrow, Oliver, Felicity, and Diggle (David Ramsey) come to Central City to investigate a death involving a deadly boomerang. We know Captain Boomerang is involved but Barry needs the Arrow and his team to help him stop the metahuman Ray Bivolo, who causes people to lose control.

5) Who Killed Sara Lance?

Part Two continues on Arrow's The Brave and the Bold as Ollie and the gang are still hunting after the boomerang-wielding killer. In the subplot, Felicity needs help from the Flash team to solve the Canary (Caity Lotz)'s murder.

Part One begins Tuesday on The Flash at 8pm on the CW. Readers, are you excited to see these two episodes?