Jane Fonda admits activism has transformed her life.

The 80-year-old actress - who was nicknamed Hanoi Jane after she was pictured sat on an anti-aircraft gun in protest against the Vietnam war in 1972 - has admitted that her life has become more meaningful since she decided to involve herself with political movements and other similar causes.

She said: ''I was a kind of pretty girl who made movies. When I decided to throw in my lot with the anti-war movement, everything shifted. Everything. The way I looked at the world and other people, people I was drawn to. Everything changed.''

Jane also revealed that while she's still proud of her fight against America's involvement in the conflict in Vietnam, she thinks the image of her sat on top of the ant-aircraft gun sent the wrong messages to the US soldiers and their families.

The New York-born star - who has just filmed an HBO documentary about her life - confessed: ''I'm proud that I went to Vietnam when I did, but what I say in the film is true: I am just so sorry that I was thoughtless enough to sit down on that gun at that time. The message that sends to the guys that were there and their families, it's horrible for me to think about that.

''Sometimes I think, 'Oh I wish I could do it over' because there are things I would say differently now.''

And despite her advancing years, Jane still feels passionate about her activism and is keen to continue her work.

The two-time Academy Award winner shared: ''I'm only 80 and there are still a few decades to go if I'm lucky, and why be alive if you're not learning and growing and changing? ... You may not be able to make your life longer, but you can make it deeper and wider.''