Even divas feel self-doubt.

“Hero” singer Mariah Carey told Page Six that despite being one of the best-selling music artists of all time, her confidence struggle is real.

“I have always had low self-esteem, and people do not recognize that,” the five-time Grammy winner said – following her recent performance at Madison Square Garden with Lionel Richie, no less.

“Growing up different, being biracial, having the whole thing where I did not know if I fit in … That is why music became such a big part of my life, because it helped me overcome those issues,” she added.

Many people who appear successful and self-assured doubt themselves behind closed doors.

Take “Grey’s Anatomy” and “Scandal” creator Shonda Rhimes, who dominates Thursday night television. Her 2015 best-selling book “Year of Yes” revealed that while she’s the reigning queen of must-see TV, she’s long suffered from almost crippling shyness that made her avoid A-list parties and speaking engagements.

And Mark Zuckerberg revealed in his recent Harvard commencement speech that he was plagued by self-doubt when everyone wanted him to sell Facebook early on. “I felt alone,” he said. “I wondered if I was just wrong, an imposter, a 22-year-old kid who had no idea how the world worked.”

“Low self-esteem is a lot more common than anyone thinks, because it’s so easy to hide,” Anneli Rufus, author of “Unworthy: How to Stop Hating Yourself,” told Moneyish.  “We always catastrophize: ‘I am the worst, I am the most incompetent, I am obviously the most scared-out-of-my-wits in this meeting,’ but that’s not true. Many people are secretly shaking in their boots.”

Dr. Simon Rego, chief psychologist at Montefiore Medical Center, paints self-esteem as a spectrum that we’re constantly moving back-and-forth on, rather than something that people do or don’t have. “Most of us have strengths in certain areas, and then there are areas that challenge us,” he told Moneyish. “We’re the sum total of all of it, not just one piece of it.”

So all three of the superstars above are confident in their abilities in at least one area – singing, writing or innovating. And they rose to the top of their fields by focusing on those strengths, rather than dwelling on their perceived weaknesses.

Give yourself credit where credit is due. Rufus suggests writing down where you excel on the job; you’re great at saving the company money, or you’re great at making clients feel good one-on-one – even if you are terrified to speak in meetings. “Pin down what your skills are, and use them to be proactive,” she said.

Then work toward getting bold. Carey poured her fears into her music, which struck a chord with listeners the world over. Rhimes spent a year saying “yes” to things she normally shied from, and not only got a best-selling book out of it, but experienced incredible things – like going on “Jimmy Kimmel” and giving a commencement speech at Dartmouth. Zuckerberg held onto Facebook despite his doubts, and is now a billionaire influencer with 2 billion monthly users.

Let’s say you’re shy, but you need to start networking. Dr. Bernardo J. Carducci, director of the Shyness Research Institute at Indiana University, suggests practicing small talk with friends and family. Then graduate to chatting with coworkers in the office until you’re ready to work it at networking events. “It’s hard at first, but it’s supposed to be hard to face what scares you,” he said. “And as you challenge yourself, your self confidence gets stronger, and you keep making more progress.”

Dr. Carducci also recommends hiring help, whether that’s working with a cognitive behavioral therapist to get to the root of your insecurities, or meeting with a job coach to polish your interpersonal skills. “If you want to get good at tennis, you hire a tennis coach,” he said. “And that coach teaches you the skills you need, building on them one at a time.” You build self-confidence piece-by-piece the same way.

Plus, your imposter syndrome carries some hidden strengths. “Self-doubt, in certain circumstances, can also keep you humble and prevent you from overestimating your strengths and making a huge leap in certain situations that could be disastrous for your company,” said Dr. Rego. “And understanding how hard we can be on ourselves also makes us more empathetic towards other people, as it gives us insight into what they may also be thinking and feeling.”