Lucy and Ethel
Lucille and Vivian, who played Lucy and Ethel, seemed chummy on screen, and in real life, they were very close friends. Desi Arnaz actually hired Vivian Vance before consulting Lucy, as they were in a bind to fill her role.
Luckily, the two women hit of off immediately and became life long friends on and off the show. After I Love Lucy wrapped, the two went on to start together on the series The Lucy Show. The only pair on screen that didn’t get along in real life were Fred (William Frawley) and Vance, who thought she was too young to play his wife.