The SLIDING DOORS star arrived at the star-studded bash looking less than glamorous, to prove busy mothers can still look good without overdoing it.
She says, "The other night, I had to go to a Stella McCartney party. Stella was naughty and said, 'Yeah there's going to be a couple of photographers there.'
"So I arrived and there was a bigger press line than for the premiere of my new movie PROOF.
"I didn't have any hair and make-up, I'd just done it myself - some concealer, tinted moisturiser, blusher, mascara and that was it."