Hedi Slimane walks into a bar…it sounds like the start of a joke. But it's not a joke for a band like Froth, who went from being an Echo Park combo with 1,528 Facebook likes to the makers of the soundtrack for the Saint Laurent show tonight. God only knows how Slimane found them, but the notion of the designer walking into a bar, hearing a band and bookin' 'em for the Saint Laurent gig has an irresistible Kid-I'm-Gonna-Make-You-a-Star twist.

Froth's Joo-Joo Ashworth graduated from El Segundo High School in 2012. Jeff Fribourg graduated from the same school in 2008. He was designing cover art for local bands, which creates a connection with Raymond Pettibon, the artist whose work Slimane portfolio-ed in his invitation (these invitations, btw, are already fashion collectibles of the highest order). Pettibon used to design the sleeves for his brother's band, the Californian hardcore legends Black Flag.

There is no one who can touch Slimane for this kind of fanboy completism in fashion. He can gloss the garage band-iness of it all with a sophisticated son-et-lumière presentation, but his spirit is with the kids who sat on the floor at tonight's show.

He's their Pied Piper. His clothes speak to them. Whose legs will ever be that stovepipe-y again? Still, Slimane is a businessman as well as a designer. Tonight, he broadened his constituency with a collection that sized the tailoring up a notch, Teddy Boy rather than speed-riven punk, drape jackets rather than shrunken bumfreezers. Plus a selection of coats so gorgeous they came from outerwear heaven: digital tweed, micro-leopard print, maxi-houndstooth mohair, a stripey thing, and best of all, a herringbone that sparkled like it had been paved with sequins.

It was a moment to reflect on how Slimane throws you a drape in green Lurex, a jacket in gold lamé leopard, a black leather blazer alive with silver studs, and all of it just fits into his steamroller design ethos. A Froth lyric intoned, "Anything you read is so easy to believe." But critics carp. Clothes speak.