Audrey Hepburn was so slim because from ages 9 to 16 she was severely malnourished during World War 2 in Holland. Among other things, she sustained herself on tulip bulbs.
When Bette Midler started her career in the early 1970s, she was the singer in a gay bathhouse in New York often accompanied by Barry Manilow on piano. Manilow produced her first album and patrons of the bath house were her first hardcore fans.
Halle Berry refused to shower for 10 days to accurately portray a drug-addicted prostitute in Spike Lee's 1991 movie Jungle Fever. She felt sorry for co-star Samuel L. Jackson, "(I played) a foul-mouthed crack-smoking hoe. It’s true (I didn’t wash), ask Sam Jackson, he had to get a whiff of it!"
Doris Day believed she was born in 1924 until her 95th birthday when the Associated Press found a birth certificate with the year 1922 on it.
Rita Hayworth began showing signs of Alzheimer's during her 40s. Even as it worsened, people blamed her behavior on her heavy drinking. She never got a proper diagnosis until 1979 and upon her death in 1987 at just 68, she would become a major public face for Alzheimer's Awareness.
Grace Kelly became close friends with dancer Josephine Baker after Kelly stormed out of a nightclub in NYC that Baker was denied entry because she was black.
Liza Minnelli only accepted the role of Lucille 2 on Arrested Development because she was asked in person by Ron Howard, who she had babysat when he was a child and she a teen.
Jennifer Lopez wearing a green Versace dress during the 42nd Annual Grammy Awards subsequently led to the creation of Google's image search.
When Cher was in 5th grade, she directed a musical for her school. When the boys didn't want to participate, she acted the male roles and sang their songs.
Emma Watson used to mouth Rupert Grint's and Daniel Radcliffe's lines during the filming of Harry Potter and the Philosopher Stone.