R. Kelly -- Birthday Cakes in My Birthday Cake (Video)

Birthday Cakes

In My Birthday Cake

R. Kelly's mind ain't telling him no ... because his body likes cake -- and for the singer's birthday, he got a special double decker ... courtesy of a real bad girl.

Kelly's friends hooked him up with a fake cake for his birthday party Thursday night at Time restaurant in Atlanta ... but the kicker was "Bad Girls Club" star Sarah Oliver who was waiting inside.

Doesn't look like he made it rain. Guess he's matured.