13 Celebs With Completely Different Birth Names

Celebs change their names all the time for a number of reasons. Whether the name is way too hard to pronounce, it was already taken by someone else or it's just plain unfortunate. Check out these stars who…aren't exactly who they say they are!

Nope, not Goldie Hawn's daughter – We're talking about Katy Perry! The singer changed her name to avoid some obvious confusion.

I wouldn't want to walk around with that last name either, the 12-year-olds would just be relentless. But here's where it gets weird -- His parents changed the family name to "Phoenix" to represent a new beginning after leaving the religion "Children of God" back in the '70s.

Leave it to Olivia Wilde to snatch up the coolest stage name on the planet. She changed the name in high school in honor of Irish author Oscar Wilde.

Her stage name was taken from a Whoopee Cushion, no joke (well…kind of a joke), and her mother told her she would do better in Hollywood with a Jewish surname -- Hence, Whoopi Goldberg.

Not much of a disguise here, but when the name was already taken, she was forced to choose a new one. But those close to her NEVER call her Emma.

In the '50s he adopted the name Michael Scott (not of Dunder Mifflin), but his agent informed him the name was taken and he had to come up with a new name immediately, on a payphone in London he looked around to notice The Caine Mutiny was playing across the street – thus becoming the Michael Caine we know today.

Demi Moore took her stage name from her first husband, Freddy Moore.

When his manager told him Zeiger was too difficult to remember, Larry chose the surname King just minutes before going on air.

That's a mouthful. She had to change her name for some obvious reasons – We now know her as Meg Ryan.

"Bruno" was a nickname given by his father when her was young, while he chose the surname "Mars" because… well, it just sounded better.

There was already a Julie Smith. There are probably hundreds of Julie Smiths – We're glad she's Julianne Moore now.

After landing her first role in Leon the Professional, Natalie changed her surname to Portman.

Martin Sheen (born Estevez) adopted the stage name Sheen to help him get acting jobs. His son Charlie Sheen adopted the stage name as well – While Martin's other children Emilio, Ramon and Renée kept the Estevez surname.