structural:expansion, structural:reformatting
As the opposite gender

Formerly, in some societies, only men could become actors. In ancient Greece and ancient Rome and the medieval world, it was considered disgraceful for a woman to go on stage; nevertheless, women did perform in Ancient Rome, and again entered the stage in the Commedia dell'arte in Italy in the 16th century; Lucrezia Di Siena became the perhaps first professional actress since Ancient Rome. France and Spain, too, also had female actors in the 16th century. In William Shakespeare's England, however, women's roles were generally played by men or boys.

When an eighteen-year Puritan prohibition of drama was lifted after the English Restoration of 1660, women began to appear on stage in England. Margaret Hughes is often credited as the first professional actress on the English stage. Previously, Angelica Martinelli, a member of a visiting Italian Commedia dell'arte company, did perform in England as early as 1578, but such foreign guest appearances had been rare exceptions and there had been no professional English actresses in England. This prohibition ended during the reign of Charles II in part because he enjoyed watching actresses on stage. Specifically, Charles II issued letters patent to Thomas Killigrew and William Davenant, granting them the monopoly right to form two London theatre companies to perform "serious" drama, and the letters patent were reissued in 1662 with revisions allowing actresses to perform for the first time.

According to the OED, the first occurrence of the term actress was in 1608 and is ascribed to Middleton. In the 19th century, many viewed women in acting negatively, as actresses were often courtesans and associated with promiscuity. Despite these prejudices, the 19th century also saw the first female acting "stars", most notably Sarah Bernhardt.

In Japan, onnagata, or men taking on female roles, were used in kabuki theatre when women were banned from performing on stage during the Edo period; this convention continues. In some forms of Chinese drama such as Beijing opera, men traditionally performed all the roles, including female roles, while in Shaoxing opera women often play all roles, including male ones.

In modern times, women occasionally played the roles of boys or young men. For example, the stage role of Peter Pan is traditionally played by a woman, as are most principal boys in British pantomime. Opera has several " breeches roles " traditionally sung by women, usually mezzo-sopranos. Examples are Hansel in Hänsel und Gretel, Cherubino in The Marriage of Figaro and Octavian in Der Rosenkavalier.

Women playing male roles are uncommon in film, with notable exceptions. In 1982, Stina Ekblad played the mysterious Ismael Retzinsky in Fanny and Alexander, and Linda Hunt received the Academy Award for Best Supporting Actress for playing Billy Kwan in The Year of Living Dangerously. In 2007, Cate Blanchett was nominated for the Academy Award for Best Supporting Actress for playing Jude Quinn, a fictionalized representation of Bob Dylan in the 1960s, in I'm Not There.

In the 2000s, women playing men in live theatre is particularly common in presentations of older plays, such as Shakespearean works with large numbers of male characters in roles where gender is inconsequential.

Having an actor dress as the opposite sex for comic effect is also a long-standing tradition in comic theatre and film. Most of Shakespeare's comedies include instances of overt cross-dressing, such as Francis Flute in A Midsummer Night's Dream. The movie A Funny Thing Happened on the Way to the Forum stars Jack Gilford dressing as a young bride. Tony Curtis and Jack Lemmon famously posed as women to escape gangsters in the Billy Wilder film Some Like It Hot. Cross-dressing for comic effect was a frequently used device in most of the Carry On films. Dustin Hoffman and Robin Williams have each appeared in a hit comedy film (Tootsie and Mrs. Doubtfire, respectively) in which they played most scenes dressed as a woman.

Occasionally, the issue is further complicated, for example, by a woman playing a woman acting as a man—who then pretends to be a woman, such as Julie Andrews in Victor/Victoria, or Gwyneth Paltrow in Shakespeare in Love. In It's Pat: The Movie, film-watchers never learn the gender of the androgynous main characters Pat and Chris (played by Julia Sweeney and Dave Foley). Similarly, in the aforementioned example of The Marriage of Figaro, there is a scene in which Cherubino (a male character portrayed by a woman) dresses up and acts like a woman; the other characters in the scene are aware of a single level of gender role obfuscation, while the audience is aware of two levels.

A few modern roles are played by a member of the opposite sex to emphasize the gender fluidity of the role. Edna Turnblad in Hairspray was played by Divine in the 1988 original film, Harvey Fierstein in the Broadway musical, and John Travolta in the 2007 movie musical. Eddie Redmayne was nominated for an Academy Award for playing Lili Elbe (a trans woman) in 2015's The Danish Girl.