Hughes will play First Lady Mary Todd Lincoln, while Johnson -- the son of "Miami Vice" star Don Johnson -- will play Lincoln's assassin, John Wilkes Booth. Beckel will play Edwin Stanton, who served as Lincoln's secretary of war.
"John Wilkes Booth has been dismissed as a scoundrel and a madman," Johnson (pictured) said of the upcoming role. "Yet I was drawn to the part because he is a fascinating character that is fanatical, yet complicated and passionate."
The two-hour "Killing Lincoln," which is being produced by Ridley and Tony Scott's Scott Free Productions, is based on Bill O'Reilly's book "Killing Lincoln: The Shocking Assassination That Changed America Forever."
The film, which will air on National Geographic Channel in early 2013, begins production in Richmond, Virginia on Monday.
