On Wednesday, in a brief, vague video teaser, the immensely popular rap-adjacent superstar Post Malone announced that something called the “Post Malone Nirvana Tribute Livestream” would be happening on his YouTube channel on Friday evening.

Nirvana purists were skeptical. Sure, the 24-year-old born Austin Post has paid homage, or at least lip service, to the rock gods before, breaking through with a catchy smash called “Rockstar” and quickly becoming the go-to guitar-wielding 20-something representing his cohort in feel-good intergenerational awards show performances (with Red Hot Chili Peppers at last year’s Grammys; with Aerosmith at last year’s MTV Video Music Awards).

On the other hand, Post Malone was born a year after Kurt Cobain died, makes narcotically sing-songy tunes and writes lyrics about wearing Versace boxers and 50-carat rings on a superyacht. It was anyone’s guess what that guy’s cover of “Heart-Shaped Box” was going to sound like.

But as it turned out? Surprisingly faithful to the original.

From the moment a contagiously grinning Post Malone walked into the frame and picked from his fleet of guitars, it was clear that he was not merely one of those come-lately fans that Cobain dissed in “In Bloom” — the kind who like to sing along but “don’t know what it means” — but a musician with a deep reverence for the Seattle trio and an intimate familiarity with its catalog. (He was also clad in a tent-like floral dress, just like the ones Cobain sometimes wore in concert — a tenderly observant detail.)