 Moffat explicitly describes the series as a sequel, rather than an adaptation, stating the Jekyll of the original story really existed, and Jackman is his "modern-day descendant dealing with the same problems".As "Jekyll and Hyde" is such a well-known phrase, Moffat labored over what to call the series, eventually deciding upon "Jekyll" because that word "carries the name Hyde".The final episode replaces the title "Jekyll" with "Hyde".