In one pic, Leto is shown playfully pulling Halsey by the neck while she smiles.
They were spotted later looking quite cosy. Leto was snapped standing close behind Halsey while the pair listened to music from behind a stand.
Leto, 44, must have a thing for 21-year-olds. The last woman he was linked to was model Valery Kaufman, who shares her youthful age with Halsey.
Halsey, on the other hand, was last spotted with Ruby Rose after Rose split with fiancee Phoebe Dahl, prompting some to speculate at a relationship.Read more for more photos of Jared Leto and Halsey canoodling: