Not that it's her most pressing concern at the moment, seeing as how she just returned to rehab, but Whitney Houston has apparently been banned from attending Prince concerts by the Purple One himself.

TMZ sources indicate that Houston and her daughter Bobbi Kristina went to several Prince shows recently, and that Whitney appeared "intoxicated."

The sources say the 'I Will Always Love You' diva wanted to join Prince on stage but his people were reluctant to allow it because they "didn't want her to embarrass herself."

Footage has surfaced showing that Houston did, in fact, appear on stage with Prince recently. The video (see clip below) is a minute long and shows Houston, seemingly in fine voice, trying to fire up with crowd while Prince's band plays a funky song.

If the reports are correct, Prince was either not pleased with Houston's state of mind during the cameo, or something else happened to make him ban the diva. The sources report the breaking point might have been excessive ticket requests from Houston's camp.

Watch Whitney Houston Join Prince On Stage