'Big Brother' Winner Rachel I'm Marrying Brendon THIS WEEKEND!!!!



She JUST won $500k on "Big Brother" Wednesday ... but Rachel Reilly says she's already dropping some of her winnings on a wedding THIS WEEKEND!!!!

Reilly and her fiance Brendon Villegas were at TRU nightclub in Hollywood last night -- when Rachel told us she's having TWO weddings ... one in Vegas and one on something called "Real Station."

WARNING: Rachel has a little problem with voice immodulation ... so, check the volume on your speakers before you press play.