New York, Sept 29 : Nicole Richie, who was spotted flaunting a fuller chest in a bikini during a Mexico vacation, might have gone under the knife, according to reports.

According to Us Weekly, sources claimed that she did undergo a breast augmentation during the summer.

"In the past, she said she wanted a lift, though we never thought she was serious," the New York Daily quoted a source as telling the magazine.

A second source admitted that despite keeping mum on the subject, `she's been open about it to friends'. (ANI)