Actress Natalie Portman attends Harvard’s Class Day on May 27 in Cambridge, Mass. (Steven Senne/AP)

Many of us have felt, at some point, that we haven’t truly earned our accomplishments. Part of impostor syndrome’s power is believing that the ultra-successful never feel like frauds.

Well, the next time you feel that way, consider Natalie Portman’s speech to graduating Harvard seniors. During the Class Day address Wednesday, Portman revealed how much self-doubt she battled after she enrolled in Harvard following the release of “Star Wars: Episode 1.”

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

Portman won an Oscar in 2011 for her performance in “Black Swan” and has racked up a number of other accolades during her acting career. But when she first came to Harvard at age 18 — after being a self-described nerd in high school — she felt incapable of meeting the “intellectual rigor” of the school.

And she was certain that her acting resume helped her through the admissions process: “I got in only because I was famous. This was how others saw me, it was how I saw myself,” she said.

Portman recalled in her speech that she enrolled in challenging classes to prove her seriousness. Among them: neurobiology and advanced Hebrew literature. But all around her, friends and classmates took up less intense classes.

“Sometimes, your insecurities and your inexperience may lead you, too, to embrace other people’s expectations, standards or values,” Portman said. “But you can harness that inexperience to carve out your own path, one that is free of the burden of knowing how things are supposed to be, a path that is defined by its own particular set of reasons.”

[Career Coach: Don’t fall prey to ‘impostor syndrome’]

Portman, who graduated with a degree in psychology in 2003, became the first Harvard graduate to win an Oscar for best actress, according to the Harvard Crimson. Upon her win, former professors and mentors described her as a diligent and intelligent student.

“It was very clear when she was a student that she is a very determined person and capable of focused effort over a sustained period,” Stephen M. Kosslyn, a former Harvard psychology professor and former dean of social sciences, told the school paper. “She is now demonstrating the results of that determination and focus.”

Alan M. Dershowitz, who said Portman was in his neuropsychology and the law class, told the Crimson that “she was a terrific student” who earned an A+ on a paper — “the highest grade in the class,” the newspaper noted.

Abigail Baird, her mentor at Harvard, told the New York Times: “I’ve taught at Harvard, Dartmouth and Vassar, and I’ve had the privilege of teaching a lot of very bright kids. There are very few who are as inherently bright as Natalie is, who have as much intellectual horsepower, who work as hard as she did. She didn’t take a single thing for granted.”

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Portman came to Harvard feeling “alarmed and intimidated by the calm eyes of fellow students” who thought the work was easy compared to high school, she said. But after years of serious coursework, she accepted that acting was her passion and not a frivolous pursuit. She couldn’t wait to get back to making films.

“I realized that seriousness for seriousness’s sake was its own kind of trophy, and a dubious one, a pose I sought to counter some half-imagined argument about who I was,” Portman said Wednesday. “There was a reason I was an actor: I loved what I do. And I saw from my peers and mentors, not only was that an acceptable reason, it was the best reason.”

During a speech at Harvard University, actress Natalie Portman encouraged students to take risks like she did by learning how to dance for "Black Swan." (Bang)