How did this harmonious hour come to be?
When are you going to do a musical considering the cast you have?
But Greg [Berlanti] was really the driving force this year about making it a reality.

Credit: CW
Whats been the hardest part about putting together crossover?The hard part really was picking the songs.
I mean, it was like, What songs were we going to use?
We went through a lot of songs, a lot of going through our own iTunes.
Were we going to use modern songs, old songs, orThe American Songbook?
And so it became this treasure hunt every night.
Wed come in, What about this song?
We hadnt even seenLa La Landwith them, but Greg had been such huge fans of theirs.
More I Cannot Wish You actually came from Victor Garber.
For Kara, I think we said onSupergirlthatWizard of Ozwas her favorite.
How could it not be?
What can you tease for some of the other characters?
How different they are from what we know of them?Yeah, we get to see everybody.
Its definitely fun to see like Malcolm Merlyn and Cisco and Winn playing very different characters inside this musical.
That I was truly in awe of.
The last time they crossed over, Barry and Kara were able to learn something from each other.
Theyre just there for each other, and it has such an easygoing energy.
Hes got a zest for life.
Darren so brings him to life.
Hed heard about it.
It was very kismet, and its so much fun to see them all reunited fromGlee.
Darren mentioned the one thing he missed out on was getting to provide some songs.I know.
By the time we closed him, we were already down the path.
So well see what people say.