Comet-san

The story revolves around Princess Comet, a twelve-year-old girl who is also the princess of the Harmonica Star country of the Triangle Nebula. She was meant to meet the prince of the Tambourine Star country at a ball, but the prince ran away to Earth instead. As it turned out, Comet is sent to Earth to find him, though she has no idea what he looks like. "He will be known by the twinkling in his eyes" is the only clue she was given to the prince's identity. Once she travels to Earth, Comet falls in love with the people she meets there as well as the planet itself, quickly becoming attached to life on Earth.
(Source: Wikipedia)