Jane Fonda had plastic surgery because she didn't want to look tired.

The 72-year-old actress admits she found the decision to go under The Knife tough, but did it because she thought it was "for her".

She said: "I recently had plastic surgery. It was a hard decision to make, and I decided if I'm going to do it, I'm going to tell the truth.

"I'm writing a book about aging, so I can't write that book and not say I've had plastic surgery. And you know, I just decided it was for me - I don't want to have bags under my eyes that make me look tired, and so forth and so on."

The former fitness guru also admits she has previously been obsessed with exercise, but has changed her opinion as she has got older.

She added to television show Entertainment Tonight: "I have, in my life, been obsessive about exercise, about most everything. But one of the good things that happens when you get older in everything comes into perspective.

"I have a new hip, I have a new knee and I'm going to soon be bionic. If I don't stay active my body stops functioning."