There is a discussion in a Facebook H50 group that Gretchen Corbett plays an uncredited role in the episode Why Wait Till Uncle Kevin Dies? (S06E08) as well as her credited appearance in Study in Rage (S07E19).

I am skeptical that Corbett is in the Uncle Kevin episode. I have put pictures of her in both her Five-O "appearances" here: https://fiveohomepage.com/corbett/

Corbett was credited for appearances in other shows around this time, and it doesn't make sense to me that she would do a cameo-like appearance in the Kevin show. This show was near the end of season seven, which was far away from A Study in Rage as far as the production order was concerned. (She has a couple of lines in the Kevin show.)

The photo in the screen shot in this discussion which suggests she is in the show is from the streaming of the show at Amazon UK, and is seen on her IMDb page (https://www.imdb.com/name/nm0179151/) (IMDb is a subsidiary of Amazon.)

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