One of them famously does all his own stunts, has boasted of being able to hold his breath for six and a half minutes, demonstrated a high-altitude low-opening parachute jump in his most recent film, and can draw from an impressive suite of martial-arts techniques.
The other got punched by Orlando Bloom in an Ibiza restaurant during an argument about a girl.
So why the hell did Justin Bieber just challenge Tom Cruise to a cage fight?
The 25-year-old singer issued the bizarre and unprovoked challenge to fight Cruise on social media on Sunday night.
It’s understandable, perhaps, that Bieber might be seeking to establish himself as a tough guy, having previously been declared the loser (on points) in his bout against Bloom.
The stunt may have backfired, however, as the internet swiftly decided that Bieber had only issued the challenge because he knew Cruise would never accept it—and also that the 56-year-old veteran of the silver screen would crush Bieber, despite being well over twice his age.
Others concluded that Bieber had simply lost his mind.
Cruise has not yet responded to the bizarre request from Bieber, however UFC champion Conor McGregor, never one to miss a chance to grab a headline, has offered to host the fight.