The 30-year-old singer and actress is so proud of her newly trim form that she wore not one but two figure-hugging outfits in one day.
The Oscar winner showed off her stunning shape in a tight little black dress as she autographed copies of her new memoir, Got This: How I Changed My Ways and Lost What Weighed Me Down in New York City.
Earlier in the day she sported a glamorous, low-cut frock as she attended another event for her book's release.
She wore a form-fitting mustard dress to the event, which was thrown by Good Housekeeping magazine.