James Nesbitt and his agent attended a meeting with Jane Tranter in late 2005 regarding the 2006 series of "Murphy's Law". At the conclusion of the meeting, she offered him a script for "Jekyll", suggesting that he might like the role. Nesbitt took the script role as a way of putting a distance between his previous work. The casting of Nesbitt as Tom Jackman and Hyde was publicised on 12 December 2005, but filming was not scheduled to begin until September 2006, increasing Nesbitt's anticipation to play the roles. Writer Steven Moffat said that the dual-role required a very skilled actor, and a well-known actor was necessary because it was such an expensive show to produce. The production team decided Nesbitt's two characters would be mainly differentiated over a change in performance rather than by extensive make-up because they wanted Hyde to be able to walk around in public without attracting attention.