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Yoko Ono (born February 18, 1933) is a Japanese multimedia artist, singer, songwriter, and peace activist who is also known for her work in performance art and filmmaking. She performs in both English and Japanese. She is known for being the second wife and widow of singer-songwriter John Lennon of the Beatles. Ono grew up in Tokyo and also spent several formative years in New York City.

During the last two years that the Beatles performed, Lennon and Ono created and attended their own public protests against the Vietnam War. On March 20, 1969, they were married at the registry office in Gibraltar and spent their honeymoon in Amsterdam, campaigning with a week-long Bed-In for Peace. They planned another Bed-In in the US, but were denied entry to the country. They held one instead at the Queen Elizabeth Hotel in Montreal, where they recorded "Give Peace a Chance". Lennon later stated his regrets about feeling "guilty enough to give McCartney credit as co-writer on my first independent single instead of giving it to Yoko, who had actually written it with me." The famous couple often combined advocacy with performance art, such as in "bagism", first introduced during a Vienna press conference, where they satirised prejudice and stereotyping by wearing a bag over their entire bodies. Lennon detailed this period in the Beatles' song "The Ballad of John and Yoko".  Lennon changed his name by deed poll on April 22, 1969, switching out Winston for Ono as a middle name. Although he used the name John Ono Lennon thereafter, official documents referred to him as John Winston Ono Lennon, since he was not permitted to revoke a name given at birth. The couple settled at Tittenhurst Park at Sunninghill, Berkshire, in southeast England. When Ono was injured in a car accident, Lennon arranged for a king-sized bed to be brought to the recording studio as he worked on the Beatles' last recorded album, Abbey Road.  The two artists collaborated on many albums, beginning in 1968 when Lennon was still a Beatle, with Unfinished Music No.1: Two Virgins, an album of experimental musique concrete. The same year, the couple contributed an experimental piece to The White Album called "Revolution 9". Also on The White Album, Ono contributed backing vocals on "Birthday", and one line of lead vocals on "The Continuing Story of Bungalow Bill." The latter marked the only occasion in a Beatles recording in which a woman sings lead vocals.

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Yoko Ono