An attempt to get Diana Rigg to appear as Emma Peel in the new series was unsuccessful, although old footage of her on the phone from two 1960s episodes of "The Avengers" ("The Winged Avenger" and "The Hidden Tiger") were used to allow the character to make a cameo appearance in the episode "K Is For Kill Part One: The Tiger Awakes": actress Sue Lloyd provided the voice of Mrs Peel for these sequences. Ian Hendry, who in the early 1960s had played Steed's original partner, David Keel, also guest-starred in one episode, "To Catch A Rat", playing a different role. "Obsession" features two of the stars of the Brian Clemens/Albert Fennell British crime-fighting action series "The Professionals": Martin Shaw and Lewis Collins.