YOU KNOW CHARLES AND DIANA?" ENthused wedding guest Isiah Thomas. "It was bigger than that!" The Detroit Piston star was exaggerating, but the Mendham Township, N.J., nuptials of velvet-voiced Whitney Houston, 28, and hip-hop B-boy and fellow Grammy winner Bobby Brown, 23, sure were one slam-dunk affair.

Just after 2 P.M. on Saturday, July 18, Whitney slipped into her $40,000 wedding gown of white French lace, pearls and iridescent beads. "She was very calm," reports designer Mark Bouwer, who helped prepare her for the occasion. "The atmosphere in her room was serene."

Outside the five-acre Houston mansion, chaos reigned. Among the 800 arrivals: The Royal Family's Jackée, Cosby kid Malcolm-Jamal Warner and Lifestyles of the Rich and Famous's Robin Leach. While a string orchestra played The Wedding March, Houston walked down the aisle under a lavender bridal lent, joining attendants in full-length purple dresses—the bride's favorite color. When Houston and Brown, looking fly in a white tuxedo, were finally pronounced husband and wife, they smooched passionately. "It was great to see how euphoric Whitney was," says Roc star Charles Dutton.

Even so, this coupling took many by surprise. After all, Whitney was raised in a middle-class home on the Baptist gospel music of her mom, singer Cissy Houston, while Bobby is a rough-and-tumble kid from the Roxbury section of Boston. He already has three children out of wedlock—Landon, 6, Laprincia, 2, and Bobby Jr., 7 months, the last two by his childhood sweetheart, Kim Ward, 23. "I'm not ready to talk about it," she says of his marriage.

Still, intimates are rooting for it. After all, the union could help smooth Brown's rough edges and end long-standing rumors that Houston is a lesbian. ("I'm not gay," she has said.) If the mood at the ceremony was any indication, the future looks rosy—er, lavender. Departing guests were given gift bags containing a bottle of champagne, a slice of wedding cake and a note: "Place this cake under your pillow and dream of your own true love."