UFO Ultramaiden Valkyrie (2002)

Princess Valkyrie crash lands on Earth like any other alien, except she lands on Kazuto, a small time bath-house owner. To save him from death she gives him part of her soul. However loaning your soul does have its ups and downs. Having halved her soul Valkyrie has reverted into her child self. Kazuto and friends, with a spaceship crashed on his bath-house, must now deal with everyday challenges and trouble while trying to figure out how to get Valkyrie back to normal... including more crash landings.