Earlier on Monday, Tom Cruise was trending on Twitter. Ordinarily, this is cause for worry as most celebrities trend due to a sudden death, or a scandal.However, Tom Cruise is trending because Justin Bieber has decided that a quiet married life is no longer satisfactory to him.The 25-year old singer posted on Twitter "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. Who is willing to put on the fight? @danawhite?"The post has brought widespread reactions with most of them wondering how the artist expects to win a fight against 56-year old Tom does-his-own-stunts Cruise.UFC fighter Conor McGregor was quick to add his own take, "If Tom Cruise is man enough to accept this challenge, McGregor Sports and Entertainment will host the bout. Does Cruise have the sprouts to fight, like he does in the movies? Stay tuned to find out!"One can't help but admit a faint admiration for McGregor's gift for self-promotion.The bizarre call out also has people all over the internet wondering about how Justin and Tom's age difference will affect the fight.The internet is waiting with bated breath to see if Tom Cruise will respond to Bieber's fighting words while others remain resolutely unimpressed.https://twitter.com/AlexTheGreatzz/status/1137913778195128320 https://twitter.com/paparazzimon/status/1137920401831366657