He may be better known as the one who got away - he who quit the Brooklyn-based indie-rock band Vampire Weekend at its prime last year.
Music buffs would also be aware that as a sought-after producer, Rostam Batmanglij - or Rostam as he calls himself these days - has done fine work for Carly Rae Jepson, Haim, Charli XCX, Solange and Frank Ocean.
He collaborated with The Walkman's frontman Hamilton Leithauser for last year's surprise and sumptuous album I Had A Dream That You Were Mine.
But who, really, is Rostam? Based on this, his luminous, outre-pop solo debut Half-Light, he is one elusive creature and a terribly cute one at that.
Call him the gremlin/mogwai of pop - he is restless, sometimes loveable, other times frustratingly obtuse, but never forgettable. Half-Light glances off mainstream pop, just like much of the output by his contemporaries, Animal Collective and Dirty Projectors, as well as that of Vampire Weekend.
It is smart. It is emotionally upfront. It is the most personal and freewheeling confession he has made. A garlanded music producer/ multi-instrumentalist and the gay son of Iranian immigrants, he has no one to impress but himself.
These are gorgeous, vertiginous melodies skiing off the slope into the ether. Traipsing from reggae shuffle to pizzicato strings, they do not cleave for anyone else's parameters.
Bike Dream is a panoramic, summery missive. A candyfloss melody woven around a carefree, Frank O'Hara-esque listing of daily happenstances, it is both humdrum and secretly thrilling.
In Wood, he is re-creating the "feeling of being in bed with someone, and dreaming something wild beside them".
A nod to his Asian heritage, the song pivots on a Bollywood riff, stitched from what he calls "cut-up tabla and digital sitar" and a dusting of violins. The words refer to an Arcadia, an idyllic escapade where one can "listen to the grass/And horses they pass".
The worldliness, that sense of adventure, is also heard in the use of Brazilian street percussion in Don't Let It Get To You, where he exhorts all to not let fear stop them from doing the thing they want.
"You're not gonna get it exactly how you want it/But that doesn't mean that you shouldn't try," he advises.
Even when he's proselytising, he does it with offbeat charm. Amid gently infectious tabla, his message, though Auto-Tuned, is crystal- clear: "We just wanna keep living in America… We just wanna change the distribution of wealth/The weapons industrial complex/and the use of/Force by sundown."
Half-Light does not shove itself in your face. It is more feline than canine, always circumnavigating at the periphery, before snuggling next to you when you are actually asleep. It is home.