Veteran comedian Joan Rivers has admitted she feels obliged to look good at all times because of her job critiquing celebrities' outfits on E! show Fashion Police.

Speaking on UK show Daybreak, the 80-year-old queen of the catty putdown said: ''How can I possibly make jokes about Rihanna if I'm looking like a piece of garbage?

"So even if I'm out walking my dogs I will try to look nice because people will try and stop you in the street and say I watch your show. 'If I don't look good I will say, 'I've just come from the gym.'''

Joan appears on Fashion Police with Kelly Osbourne, Giuliana Rancic and George Kotsiopoulos.