Hook

because I could use something like here's a ranking of doctor who knew who companions by the likely that they've seen the doctors of wiener starting off with Clara Oswald who has canonically moving on. Donna Noble has but it was a clone that was half human so only technicality number two then there's Rose Tyler who spent years fucking that exact same clone moving on. Amy Pond might have seen it in 11th hour but I would argue didn't but also definitely saw it while on the Tardis accidentally while the doctor was just butt ass naked and took a long look. Rory Williams exact same scenario only he took a long look while pretending to be embarrassed. Then there's Martha Jones who definitely didn't see it while on the Tardis but did see it in declassified unit briefings and was like damn I really did wanna tap that didn't I oh well. Then there's all of Whitaker's companions there's one more here that I forgot the name of the show was way too family friendly for them to have run into her naked there and if your argument is she was a woman how did they see her weiner my answer is not with that attitude they didn't and then finally there's Bill Potts who was the doctor's student and therefore wouldn't have seen it because of that power dynamic also if you haven't seen Pearl Mackie's season you owe it to yourself she's fantastic. Anyway all of these rankings are final my word is law and if you disagree with them you are wrong so sayeth I.
Their other posts in the index, biggest breakout first.