JoJo Grant was the main
secretary companion of the Third Doctor while he was stuck at UNIT from 1971 - 1973 (or was it the 80s? Hrmmm). She was played by Katy Manning, the second most popular porn actor of the classic series behind Colin.
She was a ham-fisted bun vendor but she was also a total qt. Brought in to replace Liz Shaw because Liz wasn't cowering in fear of the villains and whimpering while clutching onto Jon Pertwee's arm like an antisocial 5 year old enough of the time.
Ehh, alright I guess I'm being a little unfair there, she did have some moments of badassery mixed in with all the wimpy shit (especially in The Mind of Evil), and even when she was being wimpy she was still determined to do what she must, and you can't help but admire her for that.
Flashed her underwear at the camera on many occasions.
Jo first appeared in Terror of the Autons and stayed for three whole seasons until her "I've fallen in love" styled departure in The Green Death. The Doctor gave her a crystal from Metebelis 3 as a wedding present, to which she pretty much said "Awh thanks, but you need it for plot convenient reasons 5 stories from now, so no thanks". The Doctor asked her to save him a piece of her cake, if you know what I mean.
She met Sarah herself and 11 in the Sarah Jane Adventures episode Death of the Doctor, and has since been in a fuck of a lot of audios, mostly Companion Chronicles. It's through those audios where she met and traveled with Iris Wildthyme for a bit (so yes, Katy Manning was talking to herself in the booth for a few plays), and went on to meet 7 & 8 through different circumstances. Oh yeah, and she met 1 & 2 in The Three Doctors (DOCTOR ORGY).