brian mcknight & porn stars*Well, it looks like Brian McKnight has almost gone all the way down the road to Pornoville.

TMZ is reporting that McKnight, along with 15 naked porn stars and one little person got down and dirty, so to speak, at the singer’s L.A. mansion.

It happened last week when the R&B singer and some scantily clad friends filmed the highly anticipated YouPorn music video for “Let Me Show You How Your P***y Works” … his breakout XXX themed song.

We’re told Brian will be in the video … but he won’t be playing the lead role — that job will be filled by the little person … who goes by the name 5 Cent.

Sources tell us there will NOT be any hardcore sex featured in the video … but there will be some nakedness. We’re told producers are gunning to release the video sometime in the next month.

You can see more photos from the shoot here, at TMZ.