Metamorphoses (1979)

Metamorphoses is a 1979 Japanese animated anthology film, originally released by Sanrio in the United States on May 3, 1979. The film is a retelling of stories from Metamorphoses by the Roman poet Ovid, set to rock music by Arthur Simms and Pattie Brooks. In all of its five parts, the protagonists are portrayed in the form of a recurring boy and girl.

More at Wikipedia.