Solemn, saucy or just plain frothy—what most becomes the wife of a future king? One of the unwritten rules of palace protocol requires that Lady Diana Spencer, as a princess-to-be, appear hatted at public affairs. Have no fears. Lady Di, 20, is a quick study, and the betrothed of Prince Charles is earning high marks for her vivacious and varied chapeaux. "For someone who hasn't worn hats before and now has to, she is doing wonderfully well," notes a London fashion editor.

There have been a few disasters, but making the best of bonnets is plainly Lady Di's intent. For her one-of-a-kind models (at prices from $90 to $110), she relies on an Edinburgh-born milliner, John Boyd, 56. (His other clients include Prime Minister Margaret Thatcher, Princess Anne and all the Queen's ladies-in-waiting.) In London, Lady Di bounds up the stairs to Boyd's Knights-bridge arcade workrooms for her fittings. "When she tries the hats on, she giggles," says Boyd. "She sees the humor of the situation."

Meanwhile Buckingham Palace denies any hand in Lady Di's regrooming. Huffs a spokeswoman: "She is certainly getting no training from ladies-in-waiting. Lady Diana has her own ideas and style." In fact, in a quiet moment recently the former kindergarten teacher confessed, "Wearing hats gives me confidence." As for Boyd, designing for Lady Di is his crowning glory. "One looks at her face and bones," he raves, "and just carries on. She is just charming. You have no idea."