The teenager – who will release her second studio album later this year - was seen flaunting her new curves at a Jonas Brothers concert in New York last week, sparking rumours she had gone under the knife to enhance her cleavage.

However, Lindsay has blasted the reports, insisting the pair's mother Dina would never let Ali have plastic surgery.

In a post on her MySpace blog, Lindsay wrote: "Of course we have our ups and downs, but all in all my mother taught us to appreciate what we have been given. Nor would she ever encourage, or allow a 14-year-old child to alter her body.

"It is hard enough being 14 years old and you have enough insecurities to begin with, then add being in the public eye..."

Lindsay also revealed she was caught off guard when a paparazzi photographer asked her what she thought about her sister's new 'implants'.

She added: "WOW! Did you really just ask me that? She is a 14-year-old girl, and you are a paedophile! I was caught out of nowhere so I didn't really come up with the proper response at the time. There's many other things that I felt like saying, but why give it to a random guy with a camera so that he can make money!”

(C) BANG Media International
Photo: WireImage.com