According to Seventeen, actors Noah Schnapp and Millie Bobby Brown aren't just friends. They're best friends. The duo grew close through working together on "Stranger Things," of course, and frequently share their love for each other proudly on social media. 

In fact, Brown once described her co-star as "the greatest friend a girl could ask for." The ride-or-dies even participated in a friendship test, emerging with flying colors (via YouTube). According to PopSugar, they have sweet nicknames for each other, too, with Schnapp calling Brown "Mills" or "Millster," while she refers to him as "Schnipper." 

In an interview with the Build series, Brown confirmed that Schnapp is "definitely up there" among her friends because he's completely "mental" and she can never predict what he's going to do. Judging by Brown's enthusiasm, they always have a good time together, which explains how the two of them got so close so quickly. 

Proving that was absolutely the case, the "Stranger Things" duo made their triumphant return to TikTok in early March 2021, much to fans' delight, sharing a video of them dancing around to Polo Frost's "Best Ever."