Mel Gibson and Sean Penn will be working on an adaptation of Simon Winchester’s 1998 bestseller The Surgeon of Crowthorne.

Gibson has been in Dublin recently to scout locations for the film, which will use the title The Professor and the Madman - the U.S. title of the Winchester's book - according to The Irish Times. The film looks at the interactions between Sir James Murray, the first ever editor of the Oxford English Dictionary, and the eccentric contributor Dr. W.C. Minor. Minor, who will be played by Penn, was a retired army surgeon who contributed more than 10,000 entries to the dictionary while inside Broadmoor Criminal Lunatic Asylum. Gibson will play Murray. The Irish Film Board has provided co-production funding, while local actors Abigail Coburn, Zoe Moran and Rob McCormack will all have roles. Gibson famously shot his Oscar-winning epic Braveheart in Ireland in 1996, although his career has since been blighted by cases of anti-Semitism and domestic violence. He recently directed Hacksaw Ridge, which stars Andrew Garfield and opened to positive reviews at the Venice Film Festival, and he'll next be seen up on the big screen starring in Blood Father, released in Irish cinemas on 7 October.