Millie Bobby Brown is dating singer-songwriter Jacob Sartorius, a source confirms to Us Weekly. Fans have been speculating for months that the Stranger Things star, 13, and the ?Chapstick? singer, 15, have slowly evolved their friendship into a relationship. She posted a photo with him on her Instagram Story last October, and they have since exchanged several flirty comments on social media. Eagle-eyed fans were quick to point out that Brown liked one of Sartorius? tweets on January 8 that read, ?just another day w you on my mind.?