Justin Timberlake & Jimmy Fallon PROVE They're BFFs By Singing Ironic & Playing The Best Friends Challenge -- Watch!
The former *NSYNC member stopped by the late night host's show to help promote his upcoming flick Trolls and while the singer was there, he HAD to have some fun with Jimmy!
JT and the SNL alum always seem to do something musical which is why we're not surprised that their sketch was all about singing Alanis Morissette's Ironic while playing kids at summer camp. Okay, so the bit wasn't THAT great, but anytime we get to see these two sing is a treat!
PLUS, the two celebs sat down and PROVED why they're BFFs by playing the Best Friends Challenge -- and it's scary how they finish each others...
Ch-ch-check out all of Jimmy and Justin's HIGHlarious fun for yourself (below)!