You'll be very surprised to know that the names that celebrities have on their birth certificates often differ greatly from how you might know them on the big screen.
Whether for work purposes, personal reasons or simply to help avoid getting us in a complex tongue twist, A-listers have many causes to change their names.
Below, take a look at 15 of Hollywood's finest and discover what they were really called before they rose to stratospheric fame.
1. Whoopi Goldberg
Real name: Caryn Elaine Johnson
Apparently, the Sister Act actress chose the first part of her stage name from often being referred to as "a whoopee cushion" due to outbursts of frequent flatulence on stage.
2. Michael Caine
Real name: Maurice Joseph Micklewhite
Seeing as his full-name was quite the mouthful, it's no wonder that Maurice decided to change his on-screen name. Apparently, it was also to distinguish himself from his working-class background.
3. Demi Moore
Real name: Demetria Gene Guynes
Demi kept the name of her first husband when they divorced in 1984.
4. Katy Perry
Real name: Katheryn Elizabeth Hudson
Before she became a bonafide sex siren and pop queen, Katy was producing Christian music under her birth name Kathryn Hudson. To avoid confusion with actress Kate Hudson, she adopted her mother's maiden name.
5. Carmen Electra
Real name: Tara Leigh Patrick
Carmen once explained the reasons for her name change:
"When I was coming out with my debut album, there was another artist named Tara on the charts. Prince gave me my name, called me into the studio the next day, where I recorded, Carmen On Top. That’s when the name really stuck."
6. Mila Kunis
Real name: Milena Markovna Kunis
When she was 7, Milena moved to the US from the Ukraine. After enrolling her into acting classes, her parents changed her name to Mila to avoid confusion when booking roles.
If you need reminding of how far she's come, take a look at her in action in the Jupiter Ascending trailer:
7. Elton John
Real name: Reginald Kenneth Dwight
Oh, and his middle name is also Hercules. No joke.
Real name: Marshal Bruce Mathers III
A long name like that would have never even fit on the charts, so it's understandable he changed it.
9. Marilyn Monroe
Real name: Norma Jeane Baker
Despite being baptized Norma Jeane Baker, Marilyn's name on her birth certificate was actually Norma Jeana Mortenson. She didn't change her name legally until 1956 and when she married playwright Arthur Miller, she actually became Marilyn Monroe Miller, often using the initials MMM.
10. Tom Cruise
Real name: Thomas Cruise Mapother IV
Tom Cruise's papa was Thomas Mapother III, so naturally he was given the same birth name.
11. Vin Diesel
Real name: Mark Sinclair
Check out Vin putting the pedal to the metal in Furious 7:
12. Lana del Rey
Real name: Elizabeth Woolridge Grant
Here she is talking about how she came by her name herself:
13. Miley Cyrus
Real name: Destiny Hope Cyrus
In honor of her nickname "Smiley," Miley legally changed her name in 2008.
14. Olivia Wilde
Real name: Olivia Jane Cockburn
Born Cockburn, the actress changed her name to Wilde after playing in Oscar Wilde's The Importance of Being Earnest when she was at school.
15. Nicki Minaj
Real name: Onika Tanya Maraj
Back when she was Onika, the voluptuous lady actually strove to be an actress rather than a rapper. A name change was necessary if she was to make it in the music business.