Jekyll was a rather clever BBC series from 2007 written by Steven Moffat. The central idea was that Robert Louis Stevenson was recounting true events rather than fiction in his book, and that somehow his unique ability, or curse, had been passed on to one of his descendants.
James Nesbitt gave a fantastic performance in the central dual role, but there was also Dennis Lawson, Gina Bellman, Patterson Joseph, Meera Syal and Fenella Wololgar. It even had a cameo from Mark Gatiss playing Robert Louis Stevenson in flashback scenes.
It's a series that I can watch again and is my current favourite British Invaders show.