Not too long after Supergirl ended its freshman run on CBS, rumors began to swirl that the series would join ArrowThe Flash, and Legends of Tomorrow on The CW. Sure enough, that turned out to be the case, and speculation immediately turned to whether fans would see all four series crossover. Again, it did not take long for this massive crossover to be confirmed, and for news to drop that characters from all four shows would unite to battle one alien threat -- the Dominators.

During the second season of The Flash it was established that Supergirl, and her friends in National City, existed on an Earth outside of Earth-1 and Earth-2. This fact was cemented when Barry Allen accidentally traveled to Kara's Earth while trying to improve his speed in order to defeat Zoom. Given that Supergirl does not exist on the same Earth as ArrowThe Flash, and Legends of Tomorrow, fans wondered whether Flashpoint would be the catalyst that brought all four series together. This turned out not to be the case, and instead, Barry Allen will end up traveling through dimensions to recruit the Girl of Steel to his Earth's defense. And for those that wonder what Supergirl's initial introductions to Oliver Queen, Cisco, and the other heroes, will look like -- you don't have to wait any longer.

The CW has just released a new promo (above) teasing the four-part crossover, which features Barry Allen introducing Supergirl to members of Team Arrow, Team Flash, and the Legends.

Arrow, Flash, Supergirl & Legends Crossover

While the promo, not surprisingly, gives very little away, we do get to see each hero introduce themselves using their code names. It seems that Oliver starts this trend by interjecting with "Green Arrow" when Kara initially addresses him as Oliver. Predictably, we see very little else, other than a few quick glimpses at some action sequences -- and Mick Rory eating, per usual.

The four-part crossover will be unlike any seen on The CW thus far. While the Arrowverse has featured crossover episodes each season since The Flash joined the fray, they have usually acted as stand-alone stories, rather than one cohesive story. That changed last year with the two-part crossover that introduced Vandal Savage and set up Legends of Tomorrow. But a four-part crossover is an entirely different animal, and it certainly will be interesting to see whether they pull it off. Like Felicity, surely most fans are hoping this is the "best team-up ever!"

Supergirl airs Mondays at 8pm on The CW, The Flash airs in the same timeslot on Tuesdays, Arrow on Wednesdays, and Legends of Tomorrow on Thursdays.

Source: The CW (via Television Promos)