11 February 2010New photos of Hilary Duff have sparked rumours that the actress and singer may have had cosmetic surgery. At 22 years old, Hilary is still younger than many of her Hollywood contemporaries, but according to experts in the field of plastic surgery, her age has not stopped her from taking care of her appearance."Even at 22, most foreheads are not that smooth - especially when squinting in the sunlight," Dr Michael Salzhauer told Make Me Heal, commenting on a picture of the actress sporting a wrinkle-free forehead on a bright day. "She most likely had Botox injections to her forehead and in between her eyebrows for this smooth and shiny look." Another cosmetic surgeon, Dr David Shafer, agreed that the actress may have used Botox to achieve a wrinkle-free complexion, stating: "Hilary does have a slight Botox look - nice smooth skin - nothing wrong with that." The photos have also caused discussion over whether Hilary has had other non invasive surgery such as lip fillers to achieve a fuller pout. It was also previously reported that Hilary may have undergone a nose job and breast enlargement, with cosmetic surgeon Anthony Youn saying: "It is definitely possible she may have had a breast augmentation. The edges of her breast look very defined, which can be a sign of breast implants. If they are implants, they are not too big and tastefully done."