Behind thick stone walls topped by electrified razor wire, one of cyberspace's most unlikely hits is already warming up as the rest of Cebu, Philippines, stirs from sleep.

Pockets of inmates stretch and practice their latest moves. Then the morning workout gets under way in earnest in the exercise yard of the Cebu Provincial Detention and Rehabilitation Center.

In their identical orange prison uniforms, up to 1,500 march and clap in unison as they perform precision dance routines with the Village People's ''In the Navy'' and ''YMCA'' pounding from six well-worn black speakers.

And why not? Their version of Michael Jackson's ''Thriller'' had been watched nearly 4.4 million times on YouTube as of Thursday, uploaded by Byron Garcia, the Cebu provincial security consultant who came up with the idea of adding structure to poorly attended exercise sessions.

Inmates with arms covered in tattoos and baby-faced guys who might have been gang members on the outside gyrate next to one another. They all seem to be enjoying themselves or at least taking pride as their sandals and tennis shoes slap in unison on the gray concrete. They laugh when they screw up, applaud when they get a new sequence right.

Forty-four female inmates, held in a separate wing, join in for ''I Will Follow Him'' from the movies ''Sister Act,'' which is among several other songs posted on YouTube. Ten have at least 100,000 hits each.

''If I was not in prison, I would not be famous,'' said Wenjiel Resane, the male inmate who plays the role of the girlfriend in ''Thriller'' and is a featured dancer in other songs.