Washington, Jan 16 : American socialite Paris Hilton has sparked rumours that she has had her lips surgically enhanced, after she seen looking plumper in Sydney.

Though her rep has denied that she has had any alterations done to her lips, experts say that it definitely looks like she has.

"It definitely looks as though she had lip augmentation, probably with a hyaluronic acid like restylane on both lips," Fox News quoted Fifth Ave-based cosmetic surgeon and dermatologist Dr. Lewis M Feder, as saying.

Famed Beverly Hills surgeon, Dr. Payman Simoni, also supported Feder's comment.

"It seems that Paris Hilton has done what is one the most common cosmetic procedures after breast implant and that is the lip enhancement," Simoni said.

"One tell-tale sign is the white shine at the borders of her upper lip which is usually achieved by injection of Hyaluronic acid commonly known as Juvaderm or Restylane.

"In this case of Paris Hilton, her lips would have been more improved if the physician enhanced her cupid bow. But overall, she had a great (apparent) lip enhancement," he stated.

Added to the duo's comments were Hollywood's Ona Spa and Dr. Richard Fleming of the Beverly Hills Institute, who agreed that it appeared as though Hilton had undergone lip augmentation.

But 27-year-old Hilton's rep has denied all claims, saying that she has never had any type of surgery before.

"She did not do anything to her lips. She has never had any type of plastic surgery whatsoever," Hilton's manager said. (ANI)