The Doctor occasionally touched, tapped, or rubbed his cat brooch for good luck just before doing something particularly risky. (TV: The Twin Dilemma, Attack of the Cybermen, Vengeance on Varos, PROSE: Retribution, Time Wake)
Insisting that the Doctor return his coat in exchange for his own, Jack Harkness said that he would have put cat badges on it. The Doctor defended the badges, which he described as "jaunty". (AUDIO: Piece of Mind)
Behind the scenes
- One original idea for the brooch was that it would change its expression to match the mood of the current situation, for example, frightened cats when the Doctor was scared. Ultimately, this idea was dropped, though it would be subtly implemented in the illustrated webcast Real Time.
- Many fans sent cat brooches to Colin Baker; he eventually accumulated a large collection, and claims to have worn every single one. (DCOM: Attack of the Cybermen) When Baker reprised the role of the Doctor in the 1989 stage play The Ultimate Adventure, his costume contained a different brooch from his collection for each performance.