Stephen Frears directs the film about the opera singer, who was also the basis for the 2005 Broadway play-with-music , which starred Tony winner .
Grant is cast as Jenkins' manager and partner St. Clair Bayfield.
"Florence" features a screenplay by ; a release date has been set for May 6.
Jenkins, who was an eccentric society woman, , although the opposite was true. Despite her lack of talent, Jenkins' charity recitals in such venues as the Ritz Carlton Hotel brought her much fame. Jenkins often mistook audiences' muffled laughter for cheers, and over 2,000 people were turned away from her Carnegie Hall concert in the mid 1940's.
Streep was seen as The Witch in the film version of and 's Into the Woods, earning her unprecedented 19th Oscar nomination.
