6 of 15:
At the age of 37, Jack Nicholson discovered that the woman he always thought was his sister was actually his mother. FACT: Jack Nicholson was born on April 2, 1937 to 17 year old June Nicholson. Jack grew up believing that June was his sister and his maternal grandmother Ethel May was his mother. When he was 37, Jack received the official verification from June's sister, Lorraine, The Glasgow Herald reported. Pictured: Jack Nicholson in a scene from 'One Flew Over the Cuckoo's Nest.'
(Photo courtesy of Fantasy Films)