EXCLUSIVE: Margot Robbie's Biggest Insecurity Revealed — And It's Nothing to Do With Her Body

Margot Robbie's greatest insecurity is not about appearance but intelligence, with the actress admitting she once feared she might be "dumb" after choosing acting over university, RadarOnline.com can reveal

The Australian-born actress, 35, now one of Hollywood's most bankable stars, said the decision to forgo higher education after landing a role on Australian soap Neighbours left her questioning her intellect.

And a source told us her greatest fear is being dubbed a "dumb blonde," despite her massive success.

Robbie, who grew up on the Gold Coast and later broke out internationally in The Wolf of Wall Street, said as her career gathered pace, she worried skipping university might define her as less capable.

Speaking on the Smartless podcast, she reflected on the doubts that lingered even as her professional success mounted.

Robbie said: "Part of me was like, 'Oh no, I started acting like on Neighbours... I haven't gone to university, and I guess I'm never going to at this point. Am I dumb?'"

Robbie described how she turned to her sister, who was studying accounting at university, in a bid to prove something to herself. She said: "I remember asking my sister, I like almost wanted to check... this didn't mean I wasn't smart."

Her sibling, she explained, was "very, very different," pursuing a path Robbie "never would have done." Still, the actress asked to try her hand at one of her sister's assignments to prove herself. She said she asked her sibling: "Can I do one of your assignments – your uni assignments. Because I just need to check that acting's not making me dumb.'"

Despite admitting "numbers and accounting are not my forte at all," the Barbie star completed the task and excelled. She said: "And I did it. And by the way, numbers and accounting are not my forte at all, but I got like an A minus. And I was like, 'OK cool,' and I felt good after that. I'm good. I know I can do it if I need to... well, I mean, I studied. "It was all about cognitive dissonance or some boring s---."

A source close to the movie star said the fear of being dismissed intellectually still lingers beneath the surface.

The insider claimed, "Being dubbed a dumb blonde is Margot's biggest fear. She has worked incredibly hard and hates the idea that people might reduce her to a stereotype because of how she looks or because she didn't go to university."

Another industry source added: "Margot is proud of her career, but she has always been sensitive about intelligence. She wants to be taken seriously as a producer and businesswoman as well as an actress."

Robbie's candor comes alongside recollections of her early years in London before global fame. Appearing on the Table Manners podcast, she described living in Clapham with six friends in a four-bedroom apartment until 2016 – and being ejected from nightclubs with regularity.

Recalling a night at the Infernos club, she said: "So we all had a weekend in London when the job was done. And of course, we went to Infernos, and within about 15 minutes, we got kicked out. "And while we're getting dragged out by security, I was screaming, 'But this is Infernos, you can't get kicked out of Infernos.' "And the bouncer was like, 'Look, we allow most things, but when your friend does … then we kick you out.' "And I was like, 'Okay, fair enough!'"

She added, "Most of the clubs in Clapham, I'd say, have kicked us out. Yeah, for a while we were banned at a number of places! So we ended up all deciding to move in together."