Justin Bieber -- Girl Who Filmed Him Sleeping is a Porn Star

That girl who filmed Justin Bieber sleeping in Brazil may not be a hooker ... but she has been paid for sex -- at least that's what one porn site is claiming.

TMZ has learned HotMovies.com says they shot XXX video of the girl -- Tati Neves -- a few years ago ... and they plan to release it this week to come up off her newly popular name.

We've seen the scene and it's definitely your run of the mill porn ... with a slight Brazilian influence -- they're banging on a soccer field.

For what it's worth ... our Bieber sources are adamant the singer never touched Tati.

After seeing the video he may change his mind.