Theron and Reeves may not make anyone forget Tracy and Hepburn, but their movies do pair a bubbly Charlize with the stiff Keanu, making them possible cinematic foils for future exploitation by the right film maker. When you have big stars who share a connection, it's hard to get them back together in another movie, especially when one of the stars gets bigger. In another era, Tracy and Hepburn shared billing in 10 movies, and Bogey and Bacall in five. Some of these movie matings have appeal because they're cute squared. And while being cute and cuddly is often enough to launch a co-dependent career, it sometimes helps to sing, as with Mickey Rooney and Judy Garland and Nelson Eddy and Jeanette MacDonald, or dance, as in the case of Fred Astaire and Ginger Rogers, or Astaire and Cyd Charisse, or even Astaire and Gene Kelly.
Volatility is another binding factor for screen couples.
The same can be said, though slightly less sensationally, for the pairings of Corey Haim and Corey Feldman, Burt Reynolds and Sally Field, Roadrunner and Wile E. Coyote, and the aforementioned Reeves and his first multiple-movie buddy, River Phoenix. Every era has had its dominant screen team. The 1920s boasted silent movie lovers John Gilbert and Greta Garbo. The 1940s were ruled, on the comedy side, by Hope and Crosby and, on the boy-girl side, by Tracy and Hepburn. Any deep discussion of Fifties culture is incomplete without an analysis of what made Rock Hudson and Doris Day so popular, even into the Sixties, when Liz and Dick boozed and brawled their way through the decade.