The "Sorry" hitmaker raised eyebrows on Sunday, June 09, after taking to Twitter to share his wish to brawl with Cruise, suggesting Ultimate Fighting Championship (UFC) boss Dana White host the bizarre battle.
"I wanna challenge Tom Cruise to fight in the octagon. Tom if you dont take this fight your scared and you will never live it down (sic)," Bieber posted, adding, "Who is willing to put on the fight? @danawhite ?"
Neither Cruise nor White responded to the message, although UFC star Conor McGregor was quick to offer up his services to help organise the celebrity clash.
However, Bieber, 25, has since revealed he wasn't serious about stepping into the octagon with action star Cruise, 56.
"I was just playing," the singer told photographers while out and about in Los Angeles on Wednesday, June 12, admitting he was just bored when he posted the tweet, and had no idea why he decided to call out the "Mission: Impossible" actor.
According to The Blast, he then confessed, "I'm pretty sure Tom would whoop my a**...! He's out of my weight class."