Tigger

When the Eighth Doctor was split into three personalities, Charley Pollard, in order to differentiate between them, decided to call the more exuberant one "Tigger" and the more irritable one "Eeyore" after characters in Winnie the Pooh. The Doctor said that Tigger was his favourite character from the books. (AUDIO: Caerdroia)

Yasmin Khan claimed that when the Thirteenth Doctor got excited, she started bouncing around like Tigger. The Doctor replied that it could be worse; she could be Piglet. (PROSE: Molten Heart)