Adventures in Wonderland (1992)

S1E40 Welcome Back Hatter

The Hatter receives an unexpected letter announcing he’s won a magnificent castle through a mail-order contest, prompting him to get ready to leave Wonderland. The Hare feels a deep sadness at the thought of losing his best friend, but chooses to conceal his emotions to spare the Hatter's excitement and prevent any sadness from overshadowing this joyous moment.