No word on why Firth has passed but with Lee's remake set for an early 2012 shoot, the project is certainly leaving it pretty late to fill out the other two principal roles. We'd imagine they wouldn't be short of suitors but Firth is now the second highly-publicised, in-demand thesp to have turned down the project after Rooney Mara passed on the lead female role -- not to mention Christian Bale's brief flirtation with the same role Firth has turned down here.
For those who haven't seen the Korean original, "Oldboy" follows the story of a man who is mysteriously imprisioned for fifteen years and the repercussions of his quest for vegeance after his eventual release (which include some fairly dark twists and turns). Scribe Mark Protosevich, however, has used both Park's movie and the original manga (which notably doesn't have the same gut-wrenching twist) for his script with producer Roy Lee also recently adding that the remake will add "new elements, new characters and new situations" to the story. When asked about the ending, Lee slyly dodged the bullet but intriguing replied that it'll be something "fans of the original will be very happy with. In fact, some may consider it to be a bit darker."
Firth, meanwhile, is currently lensing "Arthur Newman, Golf Pro" and will move onto Jonathan Teplitzky's "The Railway Man" alongside Rachel Weisz next February which, we guess, may have posed a scheudling problem with his potential involvement with this remake. Coincidentally, Firth also turned down a role in Park Chan-wook's "Stoker," with his "A Single Man" co-star Matthew Goode (who starred in Teplitzky's last feature, "Burning Man") replacing him.