What is it exactly about RBD? Some say its just TV. After all, the telegenic, co-ed sextet was borne out of Rebelde, the Mexican soap opera about a group of high school kids that form a band.

But it's been three years now since Rebelde began airing in Mexico (the soap is now off the air in both Mexico and the United States). The RBD kids are no longer kids but young adults between the ages of 20 and 24. And yet they keep selling, more than ever before.

That, at any rate, is what's happened with Celestial, RBD's latest album, which became the top selling Latin album of 2006 for its first week of sales. Historically, among Spanish language albums, only Shakira's Fijación Oral has sold more its first week.

So, what is it about Celestial? This is sweet, catchy, bubble-gum pop that is very pleasing to the ear and whose lyrics resonate with kids of a certain age ("In your eyes there's a certain blues, that fills me with light, almost like a karma," they sing in the track "Dame"). Further, RBD are three guys and three girls, and they trade off constantly from song to song and within songs, so there's always a little bit of something for every taste. I'll also confess to actually liking this stuff.

For the most comprehensive take, give a listen to the first two tracks on Celestial. The opening "Tal Vez Despues," written by American hitmakers (and translated here to Spanish), hints clearly at U.S. pop, and indeed, RBD are about to release an English language album. The song boasts plenty of electric guitar, gritty vocals and a super catchy chorus. The ensuing "Ser O Parecer," the album's first single, is far more traditional: innocent and uplifting, the chorus a joining of all voices.

While Celestial is mostly rhythmic pop, there are also slower tracks here. They include the title track, a slow ballad that features the male voices, and begins over simple guitar before breaking out into the chorus with the full group. In contrast, "Besame Sin Miedo" has pop, dance and rock edges over crunching guitars where all the voices chime in.

RBD doesn't allow itself to get too serious or introspective. The closest they come that is in "Algún Dia," a wistful, mid-tempo ballad that highlights sweet vocals, and indeed, is the only track here devoted to one single vocalist. The point seems to be that there are voices to be heard here.

Most important, there's amusement to be had. Listen to the final track for snippets of RBD's upcoming English language album.

By Leila Cobo