From PEOPLE Magazine Click to enlarge
There's no question he's a thoroughbred: The lineage of Monaco's Andrea Casiraghi, who turns 15 next month, is peerless. His grandmother was Princess Grace, his mother is Princess Caroline, and his father was the dashing and athletic Stefano Casiraghi, who died tragically in a speedboat accident. "The Grimaldis are a really good-looking family," says British royal watcher Judy Wade. "Fine features and lovely complexions. And Andrea's got the fair looks of Grace." A family friend who knows the 5'7" young man well observes, "He is a beautiful-looking boy. He's definitely going to be a heartbreaker."

But the grandson of Prince Rainier has seen a darker side of life. Family friends say Andrea, who was 6 when his father died, was greatly affected by the loss. Still, with his mother recently remarried to Prince Ernst August of Hanover, the sensitive Andrea (he has no royal title) seems more settled and focused on the future. Currently at a private school outside Paris (siblings Charlotte, 12, and Pierre, 11, go to school in St.-Rémy-de-Provence, France), he is an accomplished skier and soccer player; as a hobby he collects Swatch watches. His first love, though, is long-distance running. Which may soon come in handy as he tries to outrun admirers. And for that he may want to seek advice from a royal across the English Channel. Britain's Prince William, after all, has plenty of experience in dealing with what the British tabloids call "the screamagers"—screaming teenagers.