Maddie Ziegler is the epitome of confidence when she's pirouetting, leaping and spinning.

But the breakout star of the reality series "Dance Moms," who went on to stun in Sia’s blockbuster “Chandelier” video, says she’s been through the wringer — especially during her formative years, growing up near Pittsburgh.

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“I have been bullied," she told TODAY. "A lot of girls think my life has been perfect. But when I was in third grade, I had really bad teeth. I still have big teeth. I had a very big gap. This boy walked up to me. He pulled apart a fork and made it a really big gap and said, ‘This is what your teeth look like.’ People bullied me for that. It’s not OK.”

Maddie Ziegler attends "LEAP!" at The Grove on August 19, 2017 in Los Angeles. Getty Images

Ziegler would eventually be home-schooled by her mother. But being the target of bullies stung. A lot.

“It made me super-insecure. I’ve learned to love (my teeth). I learned to love my flaws. It was hard,” said Ziegler. “Once I started the reality show, everyone started loving me the second I was on the show. The girls who before were like, ‘You’re ugly,’ as soon as they saw me on the show were like, ‘Let’s be best friends.’ That’s not OK. I’m not stupid. If you’re mean, it will show through.”

Ziegler says it’s still “hard” to put herself out there, even when she performs with Sia every night on her tour, even though her mom and her friends have taught her that she's perfect as she is. She’s going back on the road next month and admits that every night, she and Sia both get “super-nervous.”

Still, she’s learned to love herself, which is helpful as she’s become more and more famous. Ziegler now promotes Kalahari Resorts, stars in movies, has her own clothing line and wrote a book. On the flip side, she get trolled online, which isn't fun, but tries to ignore any barbed comments.

"Social media will always be hard on me," she says. "Being a good person is the most beautiful you can be. Your flaws are what make you, you."