Musical numbers at weddings are as big a tradition as the vows, from the horah to the flash mob to the father-daughter evolution of dance. Been waiting our whole lives for this one night. GiphyAt the wedding of Jess and Trevor, bridesmaid Katie whipped out her alter ego, Slim Katie, to spit bars on the couple's love story to the beat of "The Real Slim Shady" by Eminem. Slim Shady's got nothing on Slim Katie. GiphySlim Katie tells the tale of the couple from beginning to the wedding, gifting them with their own little rap musical, a "Hamilton" they can show their kids (except for maybe the beginning with Trevor already having a girlfriend when they started talking).Katie kills it, getting all the guests in on the action with the chorus:“We’re all here to celebrate a couple that is really great/Help me with a toast to the lovely hosts/Will the bridesmaids please/Raise your glass, raise your glass and drink?”She dedicated each chorus to a different group of guests, making sure everyone was boozed up by the finale.It's not too late to meet Katie and make her be your BFF in time for her to spit fire your own wedding. That is, if she isn't busy with her rap career.