These celebs aren’t in the know.

It takes a lot of guts to come out and admit that you don’t understand something – especially when it’s something people assume you’re a whiz at. Microsoft founder Bill Gates recently sat down for a WSJ interview with current Microsoft CEO Satya Nadella and proclaimed that quantum computing leaves him stumped.

While the computer genius admitted to having a solid understanding of physics and math, he related quantum computing to a foreign language. “I know a lot of physics and a lot of math. But the one place where they put up slides and it’s hieroglyphics, it’s quantum,” Gates told the Wall Street Journal’s Seth Stevenson. And in all fairness, when asked to boil quantum down to one sentence – Nadella wasn’t able to deliver either.

Here are four other celebrities who don’t know things they likely should:

In 2015, the “Hotline Bling” singer took to Instagram and confessed that he doesn’t know how to tie his shoes. The image captured two women bending over at his feet, helping him lace up his sneakers. Ironically, the musician just unveiled his new Air Jordan collaboration, the OVO x Jordan Brand, which has shoelaces.

Barbara Walters
There’s a lot journalist Barbara Walters can do, like interview the biggest celebrities, CEOs and newsmakers in the world. The one thing she can’t do? Drive a car. The 88 year-old co-host of The View has never had a driver’s license and never learned how to drive – but that hasn’t stopped her from showing up to conduct interviews.

Tyra Banks
She owns the catwalk, but when it comes to the kitchen — Tyra Banks has admitted her skills leave something to be desired. Now that she’s a mom though, she’s enrolled herself in a cooking class boot camp at the Culinary Institute of America so she can learn to cook meals for her son.

I have never been one to be very excited about cooking. I put all of my energy into my work and to succeeding, so instead of cooking, I eat at restaurants all the time, order in, or defrost frozen food in my microwave. That all changed the day my son was born. I do not want him to grow up thinking that cooking is what happens only in fancy or fast food restaurants. I do not want the only cooking he witnesses to be when he turns on his television and sees famous chefs create masterpieces. I want to be his chef. I want him to go to college and miss his MOMMY'S masterpieces. I want all of his friends to be fighting to come to his house to sample his mother's culinary creations. So, I did something about it. I enrolled in ad intensive Boot Camp at @theculinaryinstituteofamerica in St. Helena and I have to say, it changed my life. Come back today to experience my culinary journey in pictures…

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All the money in the world can’t buy you swim lessons. The queen of talk tv is worth an estimated $3 billion but has admitted that she doesn’t know how to swim and is afraid of the water. In 2011, she revealed that she was taking swim lessons at the age of 57.