It's almost time for Brittany (Heather Morris) and Santana (Naya Rivera) to say "I do" on Glee! But first, they have a lot of details to sort out - one of which is the guest list.

In this exclusive sneak peek from Friday's new episode (9/8c, Fox), the soon-to-be newlyweds consult with Rachel (Lea Michele) and Mercedes (Amber Riley) about their seating chart. However, tempers flare - mainly Santana's, natch - when she sees a chair saved for the one and only Sue Sylvester (Jane Lynch). Although Sue has been known to ruin her fair share of weddings (see: Will and Emma's first ceremony), Brittany has a very sweet reason for wanting her there.

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"Sue has just been such a big part of our lives," Brittany says. "You and I met because she put us in the Cheerios."

So who will win out? Plus: Why doesn't Rachel want to sit next to Sam at the ceremony? Find out in the exclusive video below:

Glee airs Fridays at 9/8c on Fox. Are you excited for Brittany and Santana's big day?