The Star of Cottonland(1984)

Wata no Kuni Hoshi

After two-month-old kitten Chibi-neko is abandoned by her former owners, she is found by 18-year-old Tokio. Although his mother is allergic to cats and has a great fear of them, she agrees to let him keep the kitten because she fears he is becoming too withdrawn after failing his university entrance exams. Chibi-neko soon falls in love with Tokio.

In her own mind, Chibi-neko is a small human who speaks in human words, although people only ever seem to hear her meow, and she believes that all humans were once kittens like her. A stray cat tells Chibi-neko of a paradise called Cottonland, where dreams can come true.

(Source: Wikipedia)