Craig Parker plays both Darken Rahl and his lookalike in "Walter".
Bridget Regan and Craig Horner play both their regular roles and two hapless thieves disguised as them in "Mirror".
Also Zedd for a few hilarious scenes.
Dyeing for Your Art: Bridget Regan's natural hair is red and curly. It was dyed dark brown and chemically straightened to play Kahlan.
Mean Character, Nice Actor: Cara, especially in the beginning, does not get along with Kahlan, at least at first. In real life, Bridget Regan (Kahlan) and Tabrett Bethell (Cara) became best friends while working on the show.
Reality Subtext: The chemistry between Kahlan and Richard was helped tremendously by the fact that Craig Horner (Richard) and Bridget Regan are very close in real life.
Why Fandom Can't Have Nice Things: Apparently part of the reason it was canceled was that some people were so vocal about their displeasure that stations didn't want to advertise the show and were reluctant to pick it up.