This doesn't need a lot of explanation -- it's Justin Bieber and Hailey Baldwin ... or shall we say Mr. and Mrs. Bieber ... mugging for Calvin Klein and booooooyyyyy does CK know how to make a damn good ad!

The couple's pals (and former couple) Kendall Jenner and A$AP Rocky are also featured in this throwback-themed/Studio 54/breakdancing montage of cool visuals that frankly just wanna make you wear Calvin Klein underwear!