Blake Lively's real name Blake Ellender Brown
The Gossip Girl actress was actually born Blake Ellender Brown. Her father Ernie's surname was Brown, before he decided to take the surname of his wife (Blake's mother), Elaine. All of the couple's children have since adopted the surname 'Lively'.
Natalie Portman's real name is Neta-Lee Hershlag
Israel-born actress Portman was born with her traditional Israeli name, Neta-Lee Hershlag, but adopted her stage name before her first film role, in Luc Besson's Leon: The Professional (1994).
Reese Witherspoon's real name is Laura Jeanne Witherspoon
Witherspoon was born Laura Jeanne Witherspoon, with 'Reese' being her mother's maiden surname—a name she later adopted for her Academy Award-winning career.
Meghan Markle's real name is Rachel Meghan Markle
While she's now left the acting world to serve as a British royal, Meghan Markle's birth name is actually Rachel—with 'Meghan' being her middle name. The duchess began using her middle name when embarking on her acting career, and she's kept it ever since.
Emma Stone's real name is Emily Jean Stone
Stone's birth name is actually Emily Jean Stone. She told W Magazine in 2017 that the name change was already registered with an Australia's Next Top Model contestant (can you believe?), causing her to opt for the slightly different 'Emma'.
Meryl Streep's real name is Mary Louise Streep
Streep was born Mary Louise Streep, and has admitted that she adopted the name 'Meryl' because of its uniqueness. Interestingly, Mary Louise is also the name of Streep's character on the second season of Big Little Lies.
Marilyn Monroe's real name is Norma Jeane Mortenson
Before becoming arguably the most famous screen icon in history, Marilyn Monroe grew up with the completely different name: 'Norma Jeane Mortenson'. She was later given her mother's maiden name, and baptised 'Norma Jeane Baker'. While deciding that she needed a more memorable name to propel her to stardom, her studio settled on the name 'Marilyn Monroe' in the mid-1940s.
Mila Kunis' real name is Milena Markovna Kunis
Born 'Milena Markovna Kunis', the That '70s Show star moved from Ukraine to the United States as a child in the early '90s. She later changed her first name to a shorter version of her actual name, prior to her work as an actress.
Brie Larson's real name is Brianne Sidonie Desaulniers
There are actually different two stories as to how Brie Larson (born Brianne Sidonie Desaulniers) settled on her stage name. One suggests that she choose it out of practicality, with the actress telling a reporter in 2014 that it was "extremely frustrating to correct people all the time" and that "Larson is a family name."
The other? In 2015, Larson told Jimmy Fallon that her stage name was inspired by an American Girl doll named Kirsten Larson. "[The doll is] actually the reason my last name is Larson," she said.
"The name of the doll is Kirsten Larson and my last name is French and very hard to say. I was so sick of it, so as a result I was like, 'I'm changing my name! I'm changing it to Larson so that Kirsten can be in our family!'"
Sophia Loren's real name is Sofia Villani Scicolone
Sophia Loren’s former husband Carlo Ponti reportedly changed the Italian siren's name early in her career to appeal to a wider audience, with her stage moniker said to be a twist on the name of the Swedish actress, Märta Torén.
Julianne Moore's real name is Julie Anne Smith
Moore's stage name is actually a combination of her two first names from birth—'Julie' and 'Anne'. She also forewent her last name from birth, Smith, and adopted the name Moore from her father.
Helen Mirren's real name is Helen Lydia Mironoff
British actress Mirren is the daughter of a Russian father, and was born Helen Lydia Mironoff, before she adopted a more anglicised version of her birth name.
Audrey Hepburn's real name was thought to be Audrey Kathleen Ruston
Sources disagree as to the exact name the Belgian-born Breakfast at Tiffany's star was given at birth, but it definitely wasn't 'Audrey Hepburn'. Some reports claim she was born Edda van Heemstra Hepburn-Ruston, with the names Edda, Audrey (the English form of the Dutch name Edda), and Andrey (the feminine version of Andrew), being found in multiple different biographies.
However, in the 2003 book Audrey Hepburn, An Elegant Spirit, her son Sean Hepburn Ferrer provided birth certificates and other documents that stated her original name as Audrey Kathleen Ruston. He also stated that during World War II, the actress's mother, the Dutch baroness Ella Van Heemstra, temporarily changed her daughter's name to Edda Van Heemstra to hide her British heritage.
Moreover, some time after Hepburn's birth, her father Joseph Victor Anthony Ruston took on the surname Hepburn-Ruston, believing himself to be descended from James Hepburn, the 4th Earl of Bothwell, which may have been inspiration for her stage name.
Demi Moore's real name is Demi Gene Harmon
Before catapulting to fame in the '90s, Moore was actually born Demi Gene Harmon. She later adopted the surname of her stepfather, Dan Guynes, before adopting the surname of her first husband, Freddy Moore. Despite later marriages with Bruce Willis and Ashton Kutcher, Moore has kept the same surname for the length of her career.
Portia de Rossi's real name is Amanda Lee Rogers
Australian actress de Rossi was actually born with the name Amanda Lee Rogers. Since her marriage to Ellen DeGeneres, her legal name is now Portia Lee James DeGeneres.
Olivia Wilde's real name is Olivia Cockburn
When choosing her stage name, the actress and director revealed she took inspiration from Irish author and poet, Oscar Wilde, after acting in The Importance Of Being Earnest. Artistic influence aside, she also explained that she chose it as a way to honour her Irish heritage.
Winona Ryder's real name is Winona Laura Horowitz
Ryder has kept her unique first name from birth, but the Stranger Things actress's last name used to be 'Horowitz', before she had it changed.
Sigourney Weaver is Susan Alexandra Weaver
Sigourney Weaver's first name is arguably one of the most unique in Hollywood history. However, many don't know that she was actually born Susan Alexandra Weaver, and picked her stage name from F. Scott Fitzgerald's novel The Great Gatsby.
Jodie Foster's real name is Alicia Christian Foster
The Silence of the Lambs actress was actually born Alicia Christian Foster. During her childhood, the two-time Academy Award winner was nicknamed 'Jodie' by friends and family, and the nickname just happened to stick.
Meg Ryan's real name is Margaret Mary Hyra
Ryan was actually born Margaret Mary Hyra, and is assumed to have changed her name for her burgeoning acting career. In the '90s, Ryan went on to become one of Hollywood's most famous rom-com stars with roles in Sleepless In Seattle and You've Got Mail.
Tina Fey's real name is Elizabeth Stamatina Fey
The writer and Saturday Night Live comedian was actually born Elizabeth Stamatina Fey, before shortening her name for her acting work. Her new first name is actually a shortening of her middle name.
Mandy Moore's real name is Amanda Leigh Moore
Moore has been performing as both a singer and an actress since she was just a teenager, and was born 'Amanda Leigh Moore', before shortening her first name to 'Mandy'.