Avril Lavigne

Avril appears to have gone from a small A-cup to a C-cup. (source)

Nicole Richie

Size-zero Nicole Richie got breast implants in late 2006! (source)

Christina Aguilera

Christina Aguilera’s breast augmentation is rumored to have boosted her from A cups to C cups. (source)

Pamela Anderson

Anderson bleached her brunette hair blond and enlarged her breasts to 32.5 cm in diameter by a famous Beverly Hills plastic surgeon (source)

Kellie Pickler

Kellie Pickler of American Idol, who got breast implants which she showed off in a return performance on American Idol in March of 2007. (source)

Salma Hayek

Hayek has nabbed the In Touch Magazine award for having the #3 best breasts in Hollywood. Her breasts seem to have gotten, for lack of a better word, gi-normous, in the last few years and are now typically seen peeping out of every dress or gown she wears out, that is, if breasts could peep.(source)

Beyonce Knowles

Her alleged breast augmentation can be seen from comparing photos taken in 2002 and 2005 that show a considerable amount of increase in her bust. (source)

Mila Kunis

25-year old Mila seems to get her good looks with a little help from a plastic surgeon, in the form of a nose job and breast augmentation. (source)

Megan Fox

Megan’s breasts are small, so if she does have implants they are very small and appear to be rather natural. It is hard to tell from the nude photos as there are many obstructions in the way, but they do appear to have the perfectly round high riding form of breast implants. (source)

Lindsay Lohan

Lindsay is rumored to have gotten her first breast augmentation when she turned 17.  Some sources say that Lohan subsequently had a second breast augmentation to improve her breasts (source)

Britney Spears

Britney Spears had a breast augmentation in 2000 following the success of her debut album. It is rumored that Spears later removed her implants and replaced them with smaller-sized implants. (source)