People reports that Chiefs star Travis Kelce just attended his 13th show of Taylor Swift's The Eras Tour, and the significance of that number is not lost on anyone.

Swift is a huge fan of the number 13 – so much so that before every show she paints a 13 on her hand for good luck. Why are those numbers so near and dear to her heart?

Swift was born on December 13, 1989 and is explained in an interview with MTV News: “I turned 13 on Friday the 13th. My first album went gold in 13 weeks. My first No. 1 single had a 13-second entry. Every time I've won an award I've been sitting in seat 13, row 13, section 13, or row M, which is the 13th letter, basically, every time a 13 comes up in my life, it's a good thing.

Swift isn't the only one who relies on superstition to give herself an extra boost of confidence. In the book Recipe for good luck, author Ellen Weinstein explored the superstitions and rituals of some of the most famous and successful people in modern history. And while some may seem strange or silly to others, Weinstein writes that beliefs, rituals and routines can “help you face the world with ambition and confidence and inspire you to continue making your own destiny.”

Here are some other superstars who used pre-show rituals to get ready to go.

• During his playing days, NBA superstar Michael Jordan wore UNC shorts underneath his Chicago Bulls uniform. They were the same shorts he wore in 1982 when he hit the game-winning jump shot that brought his college team, the University of North Carolina Tar Heels, their first NCAA championship since 1957.
• Great tennis Serena Williams has several distinct pre-performance and on-court rituals: before a match, she ties her shoelaces the same way and always bounces the ball five times before the first serve and twice before the second serve.
• Before launching into her previous show's opening monologue, Ellen DeGeneres he would probably throw a mint in the air and catch it in his mouth.
• Rihanna has said she doesn't allow anything yellow in her dressing room before a show, believing it to be bad luck.
• Football legend David Beckham has a thing against odd numbers. His wife Victoria told him Chicago Sun-Times that their house had several refrigerators, each dedicated to different types of food. “In drinks one, everything is symmetrical,” she explained. “If there are three cans, he will throw one away because it has to be an even number.”