Produced by Mythology Entertainment's Brad Fischer, James Vanderbilt and William Sherak, the upcoming film is about a singing group forced to reconnect after 30 years, reported Aceshowbiz.
Lisa Addario and Joey Syracuse penned the script.
Currently the actresses are waiting for the new draft of the script and will get a director post that.
70-year-old Hawn, Midler, 70 and Keaton, 69 last appeared together in 1996.