The German designer, who was the creative director for Chanel and Fendi, died in Paris on Tuesday.
The designer became a devoted cat owner and lavished attention on his pet after Choupette was given to him in 2012.
Lagerfeld told French magazine Numero last year that he had named the birman cat as one of the heirs of his estate.
In the interview, he said Choupette was in his will, "among others". But he added: "Don't worry, there is enough for everyone."