Natalie Portman has told graduating Harvard students to use their inexperience to their advantage, admitting she only accepted her Oscar winning part in Black Swan because she didn't know her own limitations.

Speaking to graduating students at Harvard College, Natalie, 33, said that she might not have taken the role if she had known how 'woefully unprepared' she was to pull off the intense choreography as a trained ballet dancer, but that the subsequent experience turned out to be one of the most fulfilling professionally and personally.  

"People said [Black Swan] was an artistic risk but it didn’t feel like bravery or courage to do it as I so oblivious to my own limits," Natalie says.

"The point is, if I had known my own limitations, I never would have taken the risk," she said. "And the risk led to one of my greatest personal and professional achievements.

"Make use of the fact that you don't doubt yourself too much right now because, as we get older, we get more realistic," she said.

"Accept your lack of knowledge and use it as your asset."

Natalie bagged an Oscar for the 2010 film and met her husband, choreographer Benjamin Millepied, 37, on the set  

The two married in August 2012, just over a year after Natalie gave birth to the couple's son Aleph who is now nearly four. 

In her Harvard Commencement Speech Natalie, who graduated from the college in 2003, revealed she felt insecure about being a student there because she was already an established actress - and joined just after the release of Star Wars: Episode 1.

"I’m still insecure about my own worthiness I have to remind myself, you are here today." she said.

“Today I feel much like I did when I came to Harvard Yard as a freshman in 1999.

“I felt like there had been some mistake, that I wasn’t smart enough to be in this company, and that every time I opened my mouth I would have to prove that I wasn’t just a dumb actress," she said. 

"I started choosing jobs only I was passionate about and from which I knew I could gleam a worthy experience. I was able to own my meaning and not have it dictated by box office success. By the time Black Swan came out I felt immune," Natalie continued.

"The only thing you can be best at is being your best self."

"Sometimes our insecurity and inexperience may lead you to embrace other people’s expectations of you but that inexperience can lead you to carve out your own path, one that is free of the burden of knowing how things are supposed to be defined," she adds.

Natalie talks about feeling like an outsider at school where the girls had "flat ironed hair and Prada bags" and they spoke with an accent she mimicked to fit after she moved to Long Island from Connecticut.

She faced more of the same at Harvard where her desire to be taken seriously led her to choose obscure subjects to study - among them neurobiology and advanced modern Hebrew literature.

She also touches on the very dark times she had at college: "A combination of being 19, dealing with my first heartbreak, taking birth control pills that have since been taken off the market for their depressive side effects and too much time missing daylight during the winter months led to some pretty dark times here during my sophomore year," she admits. But finding her way back to film, and realising which jobs she was and wasn't willing to take on, helped her find her true self again she says. 

"When I got to my graduation, after four years of trying to get excited about something else, I admitted to myself that I couldn't wait to go back and make more films," Natalie told the students. "I wanted to tell stories, imagine the lives of others, and help others to do the same. 

"Fear protects us in many ways, but what has served me is diving into my own obliviousness," Natalie says. "Being more confident than I should be ... trying things that you never would have tried. Your inexperience is an asset in that it will make you think in original, unconventional ways. Accept your lack of knowledge and use it as your asset."