Best team-up ever? You got that right, Felicity. Later this month, fans of the Arrowverse will finally get to see the epic four-way crossover of The CW's superhero shows. Heroes like Green Arrow, the Flash, Supergirl, and the Legends of Tomorrow will team up when they find themselves confronted by a hoard of extraterrestrial baddies. And, now, fans have their first teaser promo for the crossover.

In the short clip, you can watch as the Flash introduces Supergirl to a team of superheroes - and there's a lot of them. Oliver Queen is his ever grumpy self as he greets the Kryptonian alien, but the Legends seem a bit friendlier, even if Supergirl does stumble with White Canary's name.

If you are not familiar with The CW's annual superhero crossover, then you still have some time to brace yourselves. The upcoming event will see the squad of heroes take on a group of aliens known as the Dominators. Titled "Invasion!", the three-part crossover begins at the end of a Supergirl episode before it moves onto the other series. The story is sourced from the 1988 comic book miniseries Invasion! a la Keith Giffen, Bill Mantlo, Todd McFarlane, Bart Sears, and more. Recently, the folks at Entertainment Weekly confirmed the crossover it will closely follow the plot of the printed miniseries: various aliens will be rallied by The Dominators and then descend on Earth to terminate the growing metahuman "threat" on Earth.

For the Supergirl team, fighting the extraterrestial villains might not be that wierd, but Oliver Queen and Barry Allen might be a bit freaked out by the encounter. The 100th episode of Arrow will be tucked inside the crossover event, and the milestone story will act as a sort of breather for the team before the Dominators return in full-force. Unsurprisingly, Oliver finds himself overwhelmed by the situation he and his comrades have found himself in - but, hey! He gets to punch an alien!

"I do get to punch an alien, but not in the hundredth episode of Arrow," actor Stephen Amell told ComicBook.com at the Arrow 100th episode party two weeks ago. "The hundredth episode of Arrow begins in a very appropriate way: it begins with Oliver running."

Clearly, the Arrowverse heroes have plenty of action awaiting them later this month. The much-anticipated crossover will pit the characters against a seemingly impossible villain, and fans are already looking forward to the event's storylines. Marc Guggenheim, executive producer, has previously told fans their Invasion! arc will be one of the most "ambitious" things they have done over at The CW.

“This year, we’re doing by far the most ambitious crossover we’ve ever done. It’s basically a huge three-part story that also brings in Supergirl, so it’s crossing over all four shows. It’s telling one big epic movie of a story. It’s not setting up any other spin-offs, it’s just big, bombastic, huge action. There’s also some really poignant character moments. There’s a lot of plot lines, particularly I would say in Flash and Legends, that come to fruition in the crossover. It’s by far the most ambitious thing we’ve ever attempted. I want to say it’s by far one of the most ambitious things anyone in network television has ever attempted. It’s completely insane.”

NEXT: First Look At Invasion! Crossover Costume Alteration For Legends of Tomorrow's Steel / The Flash's Danielle Panabaker Talks Invasion! Villains / Arrowverse Actors Tease CW Crossover Updates / Arrow EP Says Invasion! Crossover Is A Faithful, Ambitious Adaptation

Supergirl airs Mondays at 8 p.m. ET/PT; The Flash on Tuesdays at the same time; Arrow on Wednesdays and DC's Legends of Tomorrow on Thursdays. All four series air on The CW. The "Invasion!" crossover will air beginning November 28.