October 2, 2007 -- "SEX and the City" spoiler alert! Mr. Big and Carrie definitely tie the knot - and it's no small-time affair. Cast and crew are shooting today from early morning until 9 p.m. at St. Patrick's Cathedral, where the wedding takes place. Carrie and her gal pals will be wearing jewels borrowed from H. Stern. Sarah Jessica Parker even gets a congrats written into the script: "Mazel Tov! I read it in Page Six," reports a woman who played a well-wisher during filming yesterday.