Producers say Peter Morgan, who wrote "The Queen," is working on a screenplay about the frontman of the band Queen, who died of AIDS in 1994.
The as-yet-untitled film will climax with Queen's barnstorming appearance at the 1985 Live Aid concert in London.
The announcement was made by GK Films, which is producing with Robert De Niro's Tribeca Productions and Queen Films.
Queen guitarist Brian May says the band supports the project. Production is due to begin next year.
Baron Cohen's comic characters include wannabe rapper Ali G, Kazakh journalist Borat and Austrian fashionista Bruno. His latest film is Martin Scorsese's "Hugo Cabret."