Jennifer Aniston
Aniston has warned against the perils of plastic surgery.Reuters

Jennifer Aniston has said she would never have plastic surgery, but resists admonishing her celebrity friends for going under the knife.

The 45-year-old spoke candidly of the pressures on women in Hollywood to defy the natural aging process.

She added that, having seen her closest friends resort to surgery in a desperate bid to hold onto their youth, she baulks at the very idea of having a nip and a tuck.

"I think, what I have been witness to, is seeing women trying to stay ageless with what they are doing to themselves. I am grateful to learn from their mistakes, because I am not injecting s**t into my face.

"I see them and my heart breaks. I think, 'Oh god if you only know how much older you look.' They are trying to stop the clock and all you can see is an insecure person who won't let themselves just age."

The Friends star, who was previously married to Brad Pitt, said her fiancée Justin Theroux is similarly opposed to the idea of any surgical enhancements.

"I have a fiancé who will put a gun to my head if I touch my face in any way," she revealed.

The Picture Perfect star said that she hopes to emulate women who have grown old gracefully like Gloria Steinem, Diane Keaton and Annette Bening.

"I am fortunate enough to know women like Gloria Steinem, who I think is one of the most stunning women on the planet, and doesn't touch her face," she said.

"Diane Keaton, Annette Bening, all of these fabulous fearless women who are flawless, they embrace it!

Her Friends co-star Courtney Cox has reportedly undergone the kind of surgical procedures that Aniston decries.

"To each their own. I don't judge it if you do it. But sometimes I wish I could beg the people I know, who I am very near and dear to, to not touch their face."