Hilary Duff's Expanding Breasts: Plastic Surgery Or Push-Up Bra?

Hilary Duff may have hit up the gym at the weekend but it appears she may have had a little surgical help to achieve her enviable new figure.

Dressed in a black workout vest top which showed off her expanding cleavage, the starlet attended an hour-long Pilates class in Toluca Lake, California.

After returning home to change into an equally body-hugging outfit, Hilary then switched to exercising her credit card at various Beverly Hills stores.

Check out our before and after pics below – do you think that Hilary's curvier look is the result of plastic surgery?

Before?                                                           After?