Tootsie

A talented actor, Michael Dorsey, who is so obnoxious that nobody wants to work with him makes a desperate career move: he dresses himself as a woman whom he calls Dorothy Michaels. She/he fools everybody and gets a major role in a TV-series.

Naturally complications arise when Michael/Dorothy falls in love with a female co-star, Julie, and Julie's father gets a crush on Dorothy/Michael. How long can Michael/Dorothy suppress his real self.

Tootsie reminds me of another fabulous comedy, "Some Like it Hot" that also makes the most of the comedy potential of mistaken sexual identities.