Celebrity mothers like Jessica Simpson and Duchess Catherine, among others, returned to their perfect physique within a few months of giving birth to their baby.

People.com shares a list of new star mothers who quickly got back in shape:

- Jessica Simpson: The singer, who welcomed her second child - son Ace - in June, was seen in a curve-hugging black dress for a dinner with fiance Eric Johnson in October.

- Penelope Cruz: The new mother-of-two gave birth to daughter Luna in July, but she pulled off a body-hugging lace gown for her first post-baby red carpet appearance at the premiere of her new film "The Counselor" in October.

- Kate Middleton: Following her son's birth in July, she was spotted in a slim-fitting, glittery Jenny Packham gown during her night out a few months later.