Justin Bieber

One of Corden’s earliest Carpool Karaokes, co-starring Justin Bieber, makes the top 10 not only because of its entertainment value, but also for how it proved—so early on—what a valuable publicity tool Carpool Karaoke could be. Entertainment writers largely picked up on what Bieber was doing when he hopped in Corden’s car: it sure seemed like a stop on a redemption tour as the singer prepared to release a new album, Purpose, later that year. More importantly? It worked. By the time Purpose dropped, Bieber had redeemed himself—largely—in the public eye. And Corden had proven that his show can be an effective tool for celebrities looking to show a new face to the public.

Also, never forget that this was when Bieber revealed that he wears each pair of his Calvin Klein underwear only once before throwing it out. Think what you want of the guy, but that is the very definition of a fun fact.