For her July 10 wedding to Canadian hockey player Mike Fisher, 30, the country queen, 27, opted for a Chantilly lace and silk organza Monique Lhuillier gown. But after the ceremony, the bride promptly changed into a strapless Lhuillier cocktail dress.
"The wedding dress was huge," Underwood tells PEOPLE in this week's issue. "I wanted to get my boogie on, so I had to change."
Also looking sharp for the wedding, which was held at Georgia's Ritz-Carlton Reynolds Plantation resort: Underwood's beloved pooch Ace, who donned a Swarovski crystal-encrusted pink tuxedo to trot down the aisle.
"Mike was like, 'He's in pink! What are you doing?' " the newlywed singer says of Ace's tux. "But he looked so handsome."
For all the details and exclusive photos of Underwood's lavish Georgia wedding, pick up this week's issue of PEOPLE, on newsstands Friday