After her success in the British show The Avengers, NBC bought Diana Rigg over to star in her own sitcom, cleverly titled Diana. It lasted half a season between 1973 and 1974. It was based on an unaired pilot called The Diana Rigg Show, and Rigg played a recent divorcee who has moved to a new town and has an apartment surrounded by supporting characters.
It all sounds a lot like The Mary Tyler Moore Show to me, and the opening titles do nothing to dispel this:
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