MoMoKo (1990)

Kentarou, your basic salaryman, co-habits an apartment with his old study mate Haruo. He's engaged to his boss's daughter, the very egocentric Reiko, who treats him like an accessory. While waiting on Reiko to meet up up with him, he comes across the quirky Momoko, an aspiring actress who sees herself as the future Japanese Marilyn Monroe. Kentarou accidentally gets her fired from her side-job and Momoko knows a perfect way for him to make it up to her: she decides to move in with him and provide for all his and her needs... together with her pet iguana, of course. Then, the situation is further complicated by Momoko actually getting a job in the same company where Kentarou works. How to keep this all a secret from his fiancée?