Who played Jonathan Steed’s original partner in the TV series “The Avengers” (ABC, 1966-69)?

In the original British TV series, “The Avengers”, Patrick Macnee’s Steed played opposite Honor Blackman as Cathy Gale.

Blackman later became known as James Bond’s love interest, Pussy Galore, in Goldfinger.

By the time the series was imported to America in 1966, Diana Rigg, as Emma Peel, had replaced Blackman.