Do you know the real names of these stars?

Julianne Moore - Julie Anne Smith told the New York Times that she had to change her name when she registered with Equity. "There was already a Julie Smith, a Julie Anne Smith, there was everything. My father's middle name is Moore; my mother's name is Anne. So I just slammed the Anne onto the Julie. That way, I could use both of their names and not hurt anyone's feelings. But it's horrible to change your name. I'd been Julie Smith my whole life, and I didn't want to change it."

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Olivia Wilde - Olivia Cockburn preferred to name herself after Oscar Wilde.

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David Bowie - David Robert Jones changed his name to avoid confusion with Davy Jones of The Monkees.

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Ringo Starr - Sir Richard Starkey MBE played the drums in The Beatles.

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Marilyn Monroe - Norma Jeane Mortenson also went by Norma Jeane Baker before she was reinvented as Marilyn Monroe.

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Meg Ryan - Margaret Mary Emily Anne Hyra took her grandmother's last name when she joined the Screen Actors Guild.

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Louis C.K. - Louis A. Székely chose a stage name that was easier for American audiences.

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Vin Diesel - Mark Sinclair chose a more interesting stage name.

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Nicolas Cage - Nicolas Kim Coppola didn't want to be defined by his famous family name.

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Joaquin Phoenix - Phoenix was born Joaquin Rafael Bottom. His parents changed the family's last name after leaving the Children of God cult. As a child, he went by the name Leaf.

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Charlie Sheen - Carlos Irwin Estévez anglicized has a real name as long as his father, Ramón Gerard Antonio Estévez, who is better known as Martin Sheen.

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Woody Allen - Allan Stewart Konigsberg started going by his nom de plume as a teenager.

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Audrey Hepburn - The actress' name was actually Audrey Kathleen Ruston.

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Nina Dobrev - Nikolina Konstantinova Dobreva changed her name after her family moved from Bulgaria to Canada when she was a child.

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Courtney Love - Courtney Michelle Harrison first used her stage name to conceal her identity while working as a stripper.

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Winona Ryder - Winona Laura Horowitz was named after the city she was born in, Winona, Minnesota.

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Iggy Azalea - The Australian singer's real name is Amethyst Amelia Kelly.

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Blac Chyna - Her real name is Angela Renée White.

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Freddie Mercury - The Queen frontman was born Farrokh Bulsara.

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Do you know the real names of these stars? - Elton John, Emma Stone, and even Meghan Markle are not who you think! Find out which names they were given at birth.

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Kit Harington - The 'Game of Thrones' actor was named Christopher Catesby Harington.

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Meghan Markle - Rachel Meghan Markle recently celebrated her 37th birthday.

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Prince Harry - Her husband also has a different official name. Meet Prince Henry Charles Albert David.

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Bono - The U2 singer was born Paul David Hewson.

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Elton John - Reginald Kenneth Dwight legally changed his name to Elton Hercules John in 1972.

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Gigi Hadid - The model's real name is Jelena Noura Hadid.

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Caggie Dunlop - The 'Made in Chelsea' personality is really named Catherine.

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Binky Felstead - Her reality show castmate was named Alexandra Elizabeth Felstead.

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Mila Kunis - Milena Markovna Kunis moved from Ukraine to the US as a child.

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Emma Stone - The 'The Amazing Spider-Man' actress is really Emily Jean Stone. Her natural hair colour is blonde.

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Brad Pitt - The Hollywood A-lister is really named William Bradley Pitt.

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Ashton Kutcher - His parents know him as Christopher Ashton Kutcher.

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Jack Black - Thomas Jacob Black just wasn't as catchy.

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Lucy Hale - The 'Pretty Little Liars' actress is named Karen Lucille Hale.

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John Legend - The self-declared legend is actually named John Roger Stephens.

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Katy Perry - Katheryn Elizabeth Hudson reportedly changed her name to avoid confusion with Kate Hudson.

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Reese Witherspoon - The award-winning actress is named Laura Jeanne Reese Witherspoon.

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Lorde - The Kiwi singer's real name is Ella Marija Lani Yelich-O'Connor.

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Miley Cyrus - Destiny Hope Cyrus was nicknamed "Smiley" as a child and later changed her name to Miley Ray Cyrus.

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Natalie Portman - The Israeli-born actress was named Neta-Lee Hershlag.

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Bruno Mars - The singer was given the name Peter Gene Hernandez at birth.

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Jennifer Aniston - The 'Friends' actress has Greek roots and her full name is Jennifer Joanna Aniston, but only because the family name was changed from Anastassakis.

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Lady Gaga - The performer is named Stefani Joanne Angelina Germanotta.

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Calvin Harris - The Scottish DJ is really named Adam Richard Wiles.

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Rihanna - Robyn Rihanna Fenty uses her middle name professionally.

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Drake - The Toronto-born rapper is named Aubrey Drake Graham.

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Lana del Rey - The singer's given name is Elizabeth Woolridge Grant.

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Snoop Dogg - Are you shocked that his real name isn't Snoop Dogg? The rapper was born Calvin Cordozar Broadus Jr.

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Jamie Foxx - The actor started out as Eric Marlon Bishop.

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Jay-Z - Before he was Hova, he was Shawn Corey Carter.

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Tina Fey - Elizabeth Stamatina Fey went for a shorter version professionally.

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Mindy Kaling - The writer, actress, and comedian is actually called Vera Mindy Chokalingam.

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Whoopi Goldberg - Caryn Elaine Johnson has said that she took her stage name from a whoopee cushion.

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Helen Mirren - The acclaimed British actress was named Helen Lydia Mironoff but her father changed the family name when she was a child.

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Alicia Keys - Alicia Augello Cook reportedly said of her name change, "It's like the piano keys. And it can open so many doors."

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Cardi B - Belcalis Marlenis Almanzar took her stage name from Bacardi.

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Demi Moore - Moore was born Demi Gene Harmon before becoming Demi Gene Guynes when her mother remarried. She took her stage name from her first husband and kept it through two more marriages.

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Frank Ocean - Christopher Edwin Breaux has been performing under the name Frank Ocean since 2005.

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