Pet boutiques and suppliers have responded to the boom with new formalwear ranging from pooch pearls and tiaras to leopard stoles and top hats. Alexis Creations, a pet-supply manufacturer in San Antonio, Texas, distributes popular canine tuxedos–$85 for Chihuahuas, $135 for Great Danes–and will introduce a red velvet suit this month. Using pets takes some extra planning; experts advise couples to check guests for allergies and place someone in charge of the animal’s needs for the day. But newlyweds say the rewards outweigh the hassles. Heather Huntington, a recent bride in Chicago, designated Mr. Big, her 50-pound border collie, as ring bearer. “He cried while we recited our vows,” she says. Now that’s puppy love.