As the Lady of the Lake wanes in power throughout the story, with each sighting we see her "necklace of fish" reducing in number. Similarly, Queen Mab's hair grows grey as her power wanes. Merlin, being a mortal who contains magic within him, only wanes in appearance with the passage of time.
Nickolas Grace and Robert Addie, best known for their roles as the Sheriff of Nottingham and Sir Guy of Gisbourne in Robin Hood (1984), have a cameo scene together in this mini-series, a nod to fans of the beloved 1980s fantasy show.
Billie Whitelaw plays Ambrosia, the foster mother of young Merlin. She also appeared in The Omen (1976) as nanny to young Damien. Adult Damien was played by Sam Neill in the third entry of The Omen film franchise, The Final Conflict (1981).