A PERTH grandmother who stunned Australia with her model-like bikini body has been blasted for "fooling" viewers about her body after appearing on British television.

Carolyn Hartz made headlines around the country earlier this year when the 70-year-old revealed an impressive beach body.

Hartz said the secret to her success was two-fold.

"You have to watch what you put it in your mouth - that's number one - and two, you have to move your legs," she said.

However, that formula, inspired after she was treated for a pre-diabetes diagnosis, came under heavy criticism when she appeared on This Morning breakfast show.

"Who is this woman fooling?" one viewer wrote on Twitter.

'"I don't eat sugar blah blah can have toxic s--- injected in my face". Her forehead can't even move."

"Are we supposed to believe she looks so young through healthy eating?!" another wrote.

"You can clearly see she's had work done on her face!"

Hartz, a mother of four, admitted to having some cosmetic work performed in the past, but claimed it wasn't the major factor behind her eternal youth.

"Yes I do get some maintenance done, but surgery is not the answer to a healthy wellbeing," she said.