The Boys in the Band.(F4)

Many southeast Asians are full of worries about China, ranging from the effects of the region's new trade pact to how to compete with Beijing for foreign investment. But for tens of millions of young Asians, there is a far more burning question at hand: who is the cutest member of F4- -Jerry, Vic, Ken or Vanness? The boy-band pop singers may be Taiwanese, but they sing in Mandarin and have Southeast Asia deep in the throes of a love affair with all things Chinese. Says Indonesian entertainment executive Daniel Tumiwa: "Mainland Chinese, Taiwanese, Hong Kongers. For ordinary people here, it doesn't matter; it's just Chinese to them. It makes no difference. F4 is huge, huge, huge."

Not to mention hot, hot, hot. F4 is the first Mandarin pop band to win a devoted--some would say fanatic--pan-Asian audience. In many places, they are even bigger than the local acts--highly unusual in Asia's widely segmented music market. Pop tastes in east Asia have traditionally been split, with the north looking to Japan and Hong Kong, and the south to their home markets. F4 has radically altered the equation. They've sold 3.5 million albums--an astonishing number on a continent where pirated CDs are the norm. In Manila last week, fans paid up to $200--the equivalent of several months' salary--to see F4 members sing and dance live. Their faces loom large on billboards advertising Pepsi along Bangkok's expressways. On streets throughout the region, children can be heard belting F4 lyrics in passable Mandarin. "This is the first time I've ever seen a group actually conquering all markets here," says Mishal Varma, Singapore-based vice president for talent relations at MTV Asia. "No one else has crossed over the way they have."

Their staggering appeal is not easy to explain--even among music experts. A la 'N Sync, they don't play any instruments and they are not great singers. Few people even know what they're singing about. But the four twentysomething band members--Jerry Yan, Vic Zhou, Ken Zhu and Vanness Wu--belt out frothy tunes with a bubble-gum beat, and possess clean-cut good looks that have landed them on magazine covers, posters, key chains, T shirts and the bedroom walls of countless teenage girls. Indeed, their most committed fans know not just their birth dates but their blood types as well. They seem to possess that elusive blend of charisma and good timing that strikes only rarely among musicians. "In life, there comes only one Elvis Presley, one Ricky Martin, one F4," says Varma.

Their wholesome image is a big selling point. In person, the bandmates tend to be exceptionally polite. During an interview, Wu, the only F4 member who speaks fluent English, tosses off lines like, "The Vanness dream is to take care of my family one day so they don't have to work so hard." Such emphasis on family values plays well with young Asians. "F4 represents something they can aspire to within reach," says Ian Stewart, CEO of The Filter Group, an Asian trend consultancy. "Compared with Robbie Williams, Asians can connect more with F4."

The band's rise began with "Meteor Garden," a slick television drama launched in Taiwan two years ago. Based on a Japanese comic book, the series revolves around a group of Taiwanese students ...