Natalie Portman talks to students at Harvard class day

Oscar winner Natalie Portman returned to her alma mater on Wednesday (27May15) and recalled how she felt she had to prove herself as a worthy student while attending Harvard University.

The Black Swan star graduated from the prestigious Ivy League school in 2003 with a degree in psychology, and more than a decade later, she was asked to be the keynote speaker at Harvard College's Class Day ceremony, an honor which she dubbed "one of the most exciting things I've ever been asked to do".

During her speech, Portman admitted that when she first enrolled to the university, as an already accomplished actress, she feared her peers thought she was not serious about her education.

She told the graduating students, "I went to a public high school on Long Island (New York). The girls I went to school with had Prada bags and flat-ironed hair. People didn't pay much attention to the fact that I was an actress. I was known for having a backpack bigger than I was, and always having whiteout on my hands.

"When I came in (to Harvard) as a freshman in 1999, I felt like there had been some mistake, that I wasn't smart enough to be in this company. When I got to Harvard just after the release of Star Wars: Episode 1, I feared people would assume I had gotten in just for being famous, and not worthy of the intellectual rigor here."

In addition to proving she was just as smart as the other students at the school, Portman admitted she also had to deal with her "first heartbreak, taking birth control that's now off the market due to its depressive side effects...", but all of those challenges ultimately led her to the realization that her true calling was ultimately acting.

She said, "I admitted to myself I couldn't wait to go back and make more films. I had reclaimed my reason."