Ashan Warnakulasuriya

It’s the pixie-cut hair and flawless skin that give her away. Emma Watson is dressed unobtrusively in a cotton flower-print French Connection dress and beige sandals, but she is unmistakable. Fans have accosted her five times in the past half hour alone. Today is the actress’s twenty-first birthday, and she is determined to spend it as she pleases—which means a leisurely mid-morning latte followed by a stroll through the Joan Miró exhibition at London’s Tate Modern. Emma ignores the stares and continues to chat animatedly about Miró’s willingness to take risks with his art. An avid painter herself—“I love it and have a need to do it”—she can talk eloquently about every picture on the wall. Her favorite is  The Farm,  a painting once owned by Ernest Hemingway that brought the artist his first taste of success outside Spain. What she admires, Emma tells me, is that Miró was both a draftsman and a painter, unafraid to combine these talents to create something that was simultan...