R. Kelly Pool Party -- Urine Trouble Now

A famous Las Vegas pool party must have a very relaxed no-pee policy ... because R. Kelly was invited to perform there over the weekend.

Wearing a Jesus piece that would make Flo Rida jealous, the "Ignition" singer (and alleged underage pee fanatic) dropped some tunes at the Rehab Pool Party at the Hard Rock Hotel on Sunday, and the crowd went bananas.

Of course the truth is, if you're going to piss in public ... there's pretty much no safer place than a Vegas pool.

Everybody does it.