I couldn’t help being reminded of the time I had spent with another gifted idol, Leonardo DiCaprio, about a decade before. I saw the simmering ardor of the teenage masses turn into unbridled hysteria after Titanic was released. But this was even more intense. The difference, I realized, was that Zac is not only an actor but also a musician, a bona fide song-and-dance man. We ladies are defenseless against such a combination.