It is reported that sibling stars Rooney and Kate Mara are making a new film with the legendary German director Werner Herzog in Dublin.
The Sunday World reports that Bucking Fastard "tells the true story of inseparable twin sisters Joan and Jean who live on the fringes of society".
The tabloid published photos of Irish-American actors Rooney and Kate Mara during filming on Dublin's Capel Street.
The Sunday World says filming has already taken place at the Pigeon House film studios in Dublin and in Naas, Co Kildare. Some scenes will also reportedly be filmed in Slovenia.
It quotes a passage from Herzog's recent book Every Man for Himself and God Against All: A Memoir regarding the inspiration for Bucking Fastard.
"I want to make a feature film about the twins Freda and Greta Chaplin," he wrote.
"In 1981 they had a short run in the British 'red tops', or tabloid newspapers, and were famous for a few weeks for being the 'sex-crazed twins' who were so infatuated with their neighbour, a lorry driver, that he took them to court and had a restraining order taken out against them.
"Their story is unique. They are the only identical twins we know of who speak synchronously."
Rooney Mara's credits include The Social Network, The Girl with the Dragon Tattoo, Carol, the Ireland-filmed The Secret Scripture, Mary Magdalene, and Women Talking.
Kate Mara's credits include 127 Hours, American Horror Story, House of Cards, The Martian, Black Mirror, and Class of '09.
Herzog's directing credits include Aguirre, the Wrath of God, Nosferatu the Vampyre, Fitzcarraldo, Grizzly Man, Rescue Dawn, and Bad Lieutenant: Port of Call New Orleans.
Filming on Bucking Fastard will reportedly continue in Dublin for the next two weeks.
