Paris and Nicole fill out... but for different reasons

It seems pregnancy agrees with Richie, who showed of her more buxom physique while out lunching with actress Mischa Barton in New York.

As for Hilton, we only guess her increased cleavage is thanks to old fashioned push-up bra trickery.

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Bosom pals: Paris Hilton and Nicole Richie have added on the pounds up top

Hilton admits to once begging her parents for permission to get breast implants as a teenager.

"Years ago, I asked my dad for a boob job and he said it would cheapen my image," the heiress said.

Meanwhile her Simple Life co-star, the usual waif-like Richie, 26, is fours months pregnant with rocker Joel Madden's baby.

Richie has repeatedly denied having an eating disorder despite shrinking to a size zero in the past few years.

She has been ordered to serve four days in jail by the end of September after pleading guilty to driving under the influence of drugs.

It seems to be a worrying trend in Hollywood. Hilton famously recently spent a highly-documented 23 days in prison herself for drink-driving.