Jessica Simpson has denied reports she has recently undergone a cosmetic lip plump - but admits she has had work done in the past. The pop star's publicist is playing down stories that suggest Simpson received lip injections last week (ends30Nov07). The aide tells America's People magazine, "Jessica did not have anything done to her lips. "She tried (injectable gel) Restylane some time ago and did not like the way that it looked or felt, so she has not had anything done since."