Its the crossoverArrowandThe Flashfans have been waiting for sinceDCs Legends of Tomorrowwas first announced.
ItsLegends, ArrowandFlashcrossing over now, so its even bigger,Flashstar Grant Gustin tells EW.
There are more characters fromArrowandFlashcrossing over that didnt crossover last year.

Credit: Katie Yu/ The CW
But Carter Hall has other plans for his long-lost love.
Cisco struggles the most because hes found something special in Kendra.
In order for her to fully fulfill her destiny, she has to leave that.

Katie Yu/ The CW
Theres a lot of conflict there.
While its heartbreaking for the unlucky-in-love Cisco, its even more so for Hawkman.
He remembers loving Kendra, and he remembers all the adventures theyve had, executive producer Andrew Kreisberg says.

Katie Yu/ The CW
And now hes staring at this woman looking at him like hes crazy.
In my mind, theyre like a bickering old couple, Hentschel says.
Hes gone through 4,000 years of loving her and getting her to love him back.

Jordon Nuttall/TheCW
Underneath it, too, hes terrified always of losing her.
Imagine youve seen everybody that you love die.
Theres that one person thats always constant.
The complicated love triangle is one of many relationship dynamics featured throughout the event.
New relationships start to develop.
Hilarity ensues, to say the least.
I think its a lot funnier, Gustin adds.
Its huge and you see a lot of characters interacting that you dont normally get to see interacting.
What comes out of Diggle is always going to be what the audience is thinking, Ramsey says.
This is how a person would respond to someone moving that fast.
How does he respond to people with wings?
you could only imagine.
Vandal Savage has a mysticism about him, Valdes says.
The characters inArrowtypically deal with a lot of brawn-related stuff.
WithThe Flash, weve been dealing with a lot of sci-fi and all sorts of science stuff.
That is really interesting to start to uncover the supernatural factor.
Bringing the crossover to life was no easy feat.
The crossovers arent easy, Gustin adds.
But when you see it, its more than worth it.
Its going to be really fun for everybody.
It works really well.
Its not a forced gimmick.
The stories could happen organically and are woven together really well.
The extra work seems to have paid off.
While the scope of the crossover is quite large, several characters are MIA.
We wanted to have a couple, but not all, Berlanti says.
The Flash-Arrowevent kicks off Tuesday at 8 p.m.
ET, and continues Wednesday at 8 p.m.
ET on The CW.