Madeleine Martin as Fionna, Roz Ryan as Cake(if you watched Flapjack, the voice will be familiar), Grey DeLisle as The Ice Queen, and Neil Patrick Harris as Prince Gumball. That's right Neil Patrick Harris is Prince Gumball!
This was all thanks to Natasha Allergi one of the AT crew who created Fiona and Cake for fun online. Small comics can be seen floating around the net of Fiona and Cake. Fans enjoyed them so much they got a episode. You can see Natasha holding a Lady Rainicorn stickey note dispenser I sent to her below.
Please come out to a AT event in the future Natasha, all the fans want to meet you!
I've already seen the episode and I can say it's amazing. Some of the things they pulled off passed the network censors are just too funny. Don't worry everything's still clean, it's just they way how some things look like there about to go. But you"ll see it for yourselves today, on Adventure Time!
Here are some unused designs from the episode post on Natasha's Tumblr
It looks like something really horrible happened, immediately followed by baking stuff.
bit about the episode, too.
" I fought for Marshall Lee( male version of Marceline)- I wrote him lines but they were cut for time! I practically begged Pen to let me work overtime to put him back in the episode, even in some small way. I wanted him to be voiced by Dante Basco"
" Adam and I really worked to make this one special. We changed it a lot, the outline actually had no Ice Queen in it at all! No ball, no crystal sword… act two used to be a date in a restaurant! We both knew we wanted more fighting, and if there had to be a date, it would be a date with swords and skulls and fighting!"
So Marshal Lee was suppose to talk, hopefully for another look into the swapped gender world we get just that.