Shirley MacLaine wrote that Gwen Verdon, who had starred in the Broadway show, suggested to her that she should pursue the lead for the film version. After MacLaine got the role, Verdon generously coached MacLaine on her performance.
Shirley MacLaine was working with a painful infected tooth that required root canal treatment, yet she was such a trouper that she kept it a secret so as not to hold up production. She wrote that she was in so much pain, she could't even remember filming one of the exhausting Bob Fosse dance numbers.
The company was filming on the day Dr. Martin Luther King was assassinated. Actress Paula Kelly was so upset that she couldn't work. Director/choreographer Bob Fosse didn't quite understand, as he was so passionate about making the film. Nevertheless, he let everyone go home early.
The original Broadway production of "Sweet Charity" opened at the Palace Theater on January 29, 1966, ran for 608 performances and was nominated for the 1966 Tony Award for the Best Musical. John McMartin reprises his role in the movie.