Natsu No Arashi! Akinai-Chū Ep 11 - Female AP & AR

Season 2 Episode 11 High School Lullaby
13 year old Jun Kamigamo is believed to be another 13 year old boy by the male protagonist Hajime Yasaka. She normally wears boy's clothes, has short hair, and has developed no real figure yet. Hajime has a crush on the main female protagonist Sayoko "Arashi" Arashiyama, a beautiful 17-year-old ghost from the WWII era. Jun in her mind really can't compete. She has a crush on Hajime, and throughout the series refuses to reveal to him she's really a girl, and thereby risk losing their friendship as "boys". They all work at a local café. On the morning of Jun's 13th birthday, normally boyish Jun wakes up as a very well developed 20-ish woman, gaining plenty of height and womanly curves. The AP process was not shown. Of course, as an adult, Jun is definitely not boyish, and is not recognized by the other characters at the café. She pretends to be her own older sister. Near the end of the episode, she ARs back to her normal 13 years old, shrinking into her waitress' clothes.