The District 9 and A-Team actor is in line to join Angelina Jolie in the Disney film, reports Deadline.
He will play King Stefan opposite Jolie's titular character in the live-action prequel to Sleeping Beauty.
The film will focus on the villain of the classic 1959 cartoon movie, exploring the reasons behind her choosing to curse the baby Princess Aurora.
Robert Stromberg will direct the film from the script by Linda Woolverton.
Copley has been announced for starring roles in Old Grave and the English-language Old Boy remake this week.
Maleficent is scheduled for release on March 14, 2014.