Well, everything, because now it is our job as fans and passionately curious people to try and predict what type of nuptials these A-listers are going to have with their respective hubby-to-be. And besides their initials and the fact that they're both marrying an Aussie man, we're anticipating a lot of differences with these brides and what they'll want for their big day.
After all, these two stars have seemingly polar opposite personalities. So while we imagine Miley walking down the sandy aisle at her beach wedding in a Bohemian chic dress, we can't see the same for Mariah, who would probably go for more of a classic, destination wedding in some luxurious place like Italy.
As for Carey's dress? Can you picture her in anything other than a ball gown fit for a princess? Exactly.
So, from the cake to the dress to the location and more, here's how we envision Miley and Mariah's nuptials going down...
Do you agree with our predictions? Sound off in the comments below!