In honor of Friday the 13th, here are thirteen stars who believe in superstitions.

In a 2012 interview with Vanity Fair, the pop sensation shared her fear that casual sex could threaten her artist development.

“I have weird superstitions about sex,” Gaga has said. “If you’re not having sex with someone who really cares about you or who really loves you they can screw up your energy. I have this weird thing that if I sleep with someone they’re going to take my creativity from me through my vagina.”

Natalie Portman's daughter Aleph Portman-Millepied came in ninth place

David Beckham

"What to Expect When You're Expecting" star Cameron Diaz has admitted to believing in some superstitions but bravely facing others.

“I knock on wood all day long...constantly," the actress told Cosmopolitan. "But I’ve also flown on Friday the 13th in a storm with a black cat on my lap, so I’m not that superstitious."

The hunky "Total Recall" star has talked about wearing the same boxers whenever production starts on a new film.

"I don't wear them to the discos and the clubs," the actor revealed in 2004. "They're only for the first day of filming. Shamrock shorts - not very glamorous!"

Benicio Del Toro

The singer's beau, Eric Johnson, reportedly proposed on 11/11/10 at exactly 11pm.

“A numerologist told Jessica that the number 11 was going to be an important number in her future, and Eric knew it. So he waited until November 11 to pop the question," purported the Enquirer.

Alba became quite superstitious while pregnant with daughter Honor in 2008. During her baby shower, the actress gave guests prayer bracelets and asked that they not be taken off until the baby was born.

"Jessica made sure everyone was wearing a leather bracelet before they all launched into a 'life, love, health' prayer. She then told them they aren't allowed to take off the bracelets until the baby is born," an onlooker told Hip-Hop Elements.

The Broadway legend and "Glee" guest star has shared her trepidations when it comes to walking under ladders.

"I have a fear of walking under ladders. It's probably because it'd be much easier for me to do so than many people. I also say a prayer right before I got out on stage so that lights never fall on me."

In a 2009 interview with the Tonight Show, Swift revealed that her lucky number is 13!

“I was born on the 13th, I turned 13 on Friday the 13th, my first album went gold in 13 weeks…also my first song that ever went #1, it had a 13 second intro.”

Back in May, the New York Post claimed that one of the biggest names in television plans his day around his superstitions.

"The Today Show" host is said to arrive at work at the exact same time each day and takes the same route to his dressing room.

Jennifer Aniston

The "Dark Knight Rises" star is superstitious about superstitions! The intense actor constantly defies common beliefs surrounding bad luck.

"I walk under ladders, I do all that stuff. I do it on purpose. I like provoking superstitions," he has said.