In the beginning of the scene introducing Matron Mama Morton (Queen Latifah) to the new inmates, Roxie Hart (Renée Zellweger) has a brief conversation with a woman smoking a cigarette. That character is played by long-time Broadway actress Chita Rivera, who portrayed Velma Kelly in the original 1975 production of "Chicago."
Director Rob Marshall wanted Catherine Zeta-Jones to wear her naturally long hair in this movie, but she insisted on the short bob. She explained to People Magazine that she didn't want her hair to fall over her face and give people a reason to doubt that she did all of the dancing herself.
The play "Chicago" was Maurine Dallas Watkins' retelling of two very public murder trials that occurred in Chicago in 1924, those of Beulah Sheriff-Annan and Belva Gaertner. Watkins covered these trials for the Chicago Tribune and wrote the character of Mary Sunshine as a self portrait. For Belva Gaertner (better known as Velma Kelly), she had a much less glitzy fate. She was acquitted and went on to have a few run-ins with the law, but ended up living a semi-normal life before dying of natural causes in California in 1965 at the age of eighty. Although in the case of Beulah Sheriff-Annan (a.k.a. Roxie Hart), it was more of a grisly end. It's true she was acquitted of murdering her lover, thanks to the skills of her highly paid attorney, who was bankrolled by her stunningly loyal husband. She repaid that debt by publicly divorcing him after her release. She married two more times before her death from tuberculosis four years later.
Producer Martin Richards approached Catherine Zeta-Jones about appearing in this movie version of the play after being wowed by her renditions of carols at a family Christmas party in Bermuda (her and husband Michael Douglas' home). Richards approached her for the role of Roxie Hart, but Zeta-Jones, though not familiar with the original show, did know that the character of Velma Kelly sang the song "All That Jazz." She only wanted to play that role because she wanted to sing that song.