At first glance, it may not seem as though Justin Bieber and Tom Cruise have much in common.
One is a 56-year-old father of three; the other is 25, newly married, and still struggling to sprout a convincing mustache.
But beneath the surface, Tommy and the Biebs actually share a lot of common ground.
Both were A-list heartthrobs in their prime (We'll leave the discussion of whether Justin is still in his prime for another day.), and both are strict adherents of controversial religious practices.
(We'll leave the discussion of whether Scientology is a real religion for another time.)
So it was more than a little surprising when Justin randomly challenged Tom to a fight on Sunday.
"I wanna challenge Tom Cruise to fight in the octagon," Bieber tweeted.
"Tom if you dont take this fight your scared and you will never live it down. Who is willing to put on the fight? @danawhite?"
As you can see, Justin isn't envisioning some scrappy street fight.
No, he wants all the pomp and circumstance of a UFC event -- star-studded crowd, fingerless gloves, an overexcited Joe Rogan -- the whole nine.
The question of why Bieber has beef with Cruise remains unanswered.
And it seems that Twitter has already moved on to predictions of who would emerge victorious should this unlikely bout ever take place.
Given the 31-year age difference involved, you might think that Justin would emerge as an odds-on favorite.
But at 5'7" (according to his publicist) and 170 pounds, Tom has a stockier build, and he's been doing his own stunts for decades.
Add to that the fact that he has the support of the evil Lord Xenu, Intergalactic Harvester of Souls, and it's not hard to see why so many believe the smart money is on Maverick.
Plus we've seen Bieber fight, and his style brings to mind a toddler frantically grasping for an out-of-reach Cheerio.
Cruise has yet to respond to the challenge, but like so many others on social media, he's probably just concerned for Justin's mental health.
The singer has struggled with anger issues in the past, but he claimed to have put all that behind him when he found Jesus and married Hailey Baldwin.
So is this a sign that Justin is returning to his old ways?
Is there any truth to the rumors of trouble in Bieber and Baldwin's marriage?
And if Justin is straying off course, will Cruise knock his ass out before shimmying across the ring to the opening strains of Bob Seeger's "Old Time Rock and Roll"?
Probably not, but even so -- messing with Tom is decidedly risky business.