Zacmaster and postmanthe -
your examples are not 'pop stars', they are musicians.
A pop star in the sense I am using the adjective is someone who is used to front professionally written and recorded songs by management companies who regard pop as a product to market and create profit. The input of the singer is minimal, if required at all, they simply turn up, wear what they are told, sing the song, and suceed or fail.
A supreme example of the success of this formula is Girls Aloud - who by no coincidence at all are all drop-dead gorgeous.
I repeat - the world does not like fat pop stars - but music fans., for whom image is not relavent, but who base their appreciation on talent and ability will always embrace anyone with skill, regardless of looks, which are very much the last consideration. In the world of pop, appearance is first - above everything else.