One actor, many roles. As twins, siblings or unwitting doubles, dual-role films such as Tom Hardy's Legend tend to play either as broad comedies or intense thrillers about psychos. Whatever the genre, though, each film is designed to show off an actor's allegedly impressive range. Herewith, a quick rehash of past awards-bait projects:
The swashbuckling dual
Whether it's an episode, movie or the premise of a play (Blood Brothers), most projects that get at the nature/nurture question are born of The Corsican Brothers, the frequently adapted 1844 adventure novella by Alexandre Dumas (most famously with Douglas Fairbanks Jr. in the 1941 role). Mario and Lucien are the famous Siamese twins separated at birth, raised separately and in greatly different circumstances who, despite all this, fall for the same woman. Small world! (Jackie Chan stars in a martial-arts version.)
The teen dual
Oh, those charming switcheroos! The Parent Trap (1961) made a killing for Disney and made Hayley Mills a star (and later did the same for Lindsay Lohan in the remake). It's arguably the heartwarming tween shenanigans that started it all and led to Francine Pascal's beloved Sweet Valley High series, with brainy/cheerleader twins Elizabeth and Jessica Wakefield etched into the psyche of Gen X and Y.
The Cronenberg dual
The art-house psycho-drama with state-of-the-art sleight of hand Dead Ringers (1988) chronicles twins Beverly and Elliot Mantle, both played by Jeremy Irons, two complex brothers who have an inseparable, obsessive relationship. One an introvert, the other stylish and assertive, the two gynecologists share a flat, a practice and even date nights (in a wink, played by an actual set of wins – Jacqueline and Jill Hennessy).
The comedy dual
Be it deadpan with Alec Guinness as eight members of an aristocratic English family in Kind Hearts & Coronets or more broadly, with Peter Sellers offering pratfalls and accents in triplicate in Dr. Strangelove. The female counterpart is Lily Tomlin, who has the title role as well as that of a nosy neighbour in The Incredible Shrinking Woman (1981), and a latter-day Sellers is Eddie Murphy, who's taken on multiples in Coming to America, The Nutty Professor and others. More ironic than comedic, there's Nicolas Cage as writer Charlie Kaufmann and his bombastic brother, Donald, in Adaptation.
The millennial dual
For Armie Hammer's scene-stealing turn as identical twins Tyler and Cameron Winklevoss in The Social Network, he worked with actor Josh Pence and an acting coach for nearly a year. Hammer wasn't technically, or at least not entirely, playing both parts, since both actors played the scenes together and Hammer's face was digitally grafted onto Pence's body.
The film-noir dual
When Olivia de Havilland played an ill-fated set of siblings in The Dark Mirror (1946), the studio touted a stunning new "split-screen technology." It must have been a very good year in a cozier coastal New England setting, as Bette Davis plays sisters Patricia and Kate in A Stolen Life, with her duplicitous twin as a romantic rival in the melodrama. Davis must have liked the challenge, as just a few years later she did double-duty again in Dead Ringer.
The postmodern dual
You might also call this one the Dostoyevsky dual, with a ghostly doppelganger slowly effecting the two Jakes (Gyllenhaal) in Denis Villeneuve's Enemy (2013) in a brutalist Toronto, while Jesse Eisenberg faced off that same year with the same challenge – himself – in Richard Ayoade's The Double.
The daytime dual
Soap operas' frequent plot twist of long-lost twins is an acting-chops challenge and sweeps-week catnip – see Anne Heche (Marley and Vicky Hudson on Another World). In the 1980s, after years of playing Frannie Hughes on As the World Turns, Julianne Moore added uncanny lookalike half-sister Sabrina to her daily repertoire, too, winning an Emmy for her troubles. As did the late, great David Canary, who spent three decades playing All My Children's cunning Adam Chandler and his meek, soft-spoken brother Stuart.
The space-station dual
In a cue from Andrei Tarkovsky's Solaris, the isolation of the Moon (2009) research station allows Sam Rockwell to stretch his acting muscles and explore the splintering of ego and self as deteriorating clone versions of his original character.