Donald David Dixon Ronald O’Connor (August 28, 1925 – September 27, 2003) was an American dancer, singer, and actor who came to fame in a series of movies in which he co-starred alternately with Gloria Jean, Peggy Ryan, and Francis the Talking Mule.
He is best known today for his role as Don Lockwood's friend and colleague Cosmo Brown in Singin' in the Rain (1952).
He is also known as Donald David Dixon Ronald O’Connor.
O'Connor had undergone quadruple heart bypass surgery in 1990, and he nearly died from double pneumonia in January 1998. He died from complications of heart failure on September 27, 2003, at age 78 at the Motion Picture & Television Country House and Hospital, in Woodland Hills, California. His remains were cremated and buried at the Forest Lawn–Hollywood Hills Cemetery in Los Angeles.
O'Connor was survived by his wife, Gloria, and four children. Gloria O'Connor died from natural causes on June 4, 2013, aged 84.