There are two kinds of performers in this world: the ones who grab the mic and trust their lungs—and the ones who trust the backing track. For some artists, lip syncing is a practical evil of big televised productions. For others, it’s practically a moral offense. Over the years, we’ve seen bold refusals, hilarious rebellions, and spectacular meltdowns when the track kept playing but the singer very much did not.

Hollywood has always loved a transformation story. Sometimes it takes wigs and posture shifts to stretch decades; other times, conviction alone bridges the gap. These performances blur arithmetic and challenge casting expectations. Scroll ahead to see how actors reshaped time itself on screen.

Before Hollywood ever put a camera in his face, Robert Mitchum had already lived through things most leading men only pretended to survive. By the time he was old enough to vote, he had a record, a reputation, and a stare that didn’t come from acting lessons. The studios didn’t create his edge. They just recognized it.