Actors don't team up with director Michael Mann unless they want to flex their machismo acting chops.
And with 'Ali,' Mann and Smith tackled one of the most ambitious biographical films ever made while its subject was still alive.
Most critics loved 'Ali,' a number of whom wrote that, like his subject, Smith "soared like a butterfly."
That's the kind of critical praise that gets a mainstream actor his first Oscar nomination.
(It didn't help 'Ali's' box office. The film raked in about $87 million total against a reported cost of well over $100 million.)