ROURAN BAOBEI

From Anime Planet: Qi An is living a double life working two jobs to pay for his sick father's medical care. By day he's a timid, bespectacled office worker, at night he transforms into Yi You, a gorgeous singer who is #1 at the Chaos gay bar. When You Du, an old flame from Qi An's past, pays an exuberant amount of money for an evening with "Yi You", the two men spend a passionate night together. The magic dissolves the next day, however, when Qi An goes into the office and finds out that You Du has become his new boss!