Kelly Osbourne‘s dress size – normal or not? Is Kelly Osbourne’s dress size perfect? Has Kelly Osbourne’s dress size changed recently? Is Kelly Osbourne fat? Well, some would say that she is still fat. Others would completely disagree. Personally, I do not think she is fat. I think she looks great, but given what we have heard about Kelly Osbourne’s weight and Kelly Osbourne’s diet plan, it is understandable why people do not expect her to be a size zero. And guess what? She is not a size zero. What is her dress size? There is no official number, as usual, but according to some estimates, Kelly’s dress size is a size four.