Young celebrities working with high fashion brands is not a new phenomenon. However, teenage actors representing high fashion brands in international campaigns feels like a rite of passage that is required of very young stars in the social media era. This is particularly striking when one examines the cast of Stranger Things. Natalia Dyer, Charlie Heaton, and Joe Keery, ostensibly the "young adult" cast members of the show, have not featured in any high fashion ad campaigns despite regularly attending fashion week shows. Instead, it is their younger co-stars who are the staples of high fashion ad campaigns.
While high fashion brands are working hard to appeal to younger audiences by hiring teenagers to be the faces of their brands, teens do not make up the consumer demographic of these luxury brands. Teens may follow the campaigns these stars are featured in, and may post them to the point of ubiquity on social media, but these same teens are not spending $300 on plain white t-shirts.
To whom are these brands trying to appeal by featuring famous teens in their ads? Because it's not their consumer demographic.
It can be argued that the world of high fashion makes its bread and butter on teen models selling their products. However, let's compare the Stranger Things kids to the Harry Potter cast: Emma Watson didn't star in a high fashion campaign until she was 19 (Burberry, 2009)... and that's it for the HP cast. No other major young actor starred in a high fashion campaign during the run of that film series.
What's changed so much since the last time there was a world famous group of teen actors? Is it just the emergence of social media?
While there are age restrictions for models who walk in fashion week shows, and even who star in campaigns, the same does not exist for Hollywood stars outside of the world of fashion.
ETA: Per poisoned_summer, I want to clarify an additional issue with precisely which members of the Stranger Things cast are consistently chosen as high fashion brand ambassadors. Caleb McLaughlin, who is the young cast member most known as fashion-conscious and sartorially risk-taking, does not have a high fashion brand deal. So while it's highly questionable as to why these brands want to work with these teens in the first place, the fact that they are working with them is not up for debate. The fact that they are not also working with Mr. McLaughlin in the same way as, say, Finn Wolfhard and Noah Schnapp, is also questionable.
For additional context, and also ??? of fashion industry choices, here is a breakdown of brand deals:
Millie Bobby Brown, 15: Calvin Klein, Moncler
► Millie Bobby Brown is currently the face of two major fashion brands, and also works with Converse.
► Brown has been representing Calvin Klein for almost three years (since she was 12).
Sadie Sink, 17: Kate Spade, Miu Miu
► Sadie Sink has not only starred in multiple campaigns for Miu Miu and Kate Spade, she has also walked in two PFW shows despite being, like, 5’3 tops.
► Sink also featured in a Nike Running campaign last year and co-starred in a Pull&Bear capsule collection with Finn Wolfhard.
Finn Wolfhard, 16: Saint Laurent
► Finn Wolfhard was very recently announced as the new face of Saint Laurent.
► Wolfhard also starred in a Pull&Bear capsule collection with co-star Sadie Sink.
Noah Schnapp, 14
► While Noah Schnapp has not yet featured in a campaign, he has posted paid sponsored posts on Instagram for both Fendi and Lacoste.
► Caleb McLaughlin, perhaps the most openly fashion-conscious of the younger cast, has yet to book a high fashion campaign or make any high fashion-related paid sponsored posts on social media.
► McLaughlin does have a brand partnership with Nike, and is known as a sneakerhead.
Sources: 1 2 3