Title: GENERATIVE MODEL-ENHANCED HUMAN MOTION PREDICTION. Abstract: The task of predicting human motion is complicated by the natural heterogeneity and compositionality of actions, necessitating robustness to distributional shifts as far as out-of-distribution (OoD). Here we formulate a new OoD benchmark based on the Human3.6M and CMU motion capture datasets, and introduce a hy- brid framework for hardening discriminative architectures to OoD failure by aug- menting them with a generative model. When applied to current state-of-the-art discriminative models, we show that the proposed approach improves OoD ro- bustness without sacrificing in-distribution performance, and can theoretically facilitate model interpretability. We suggest human motion predictors ought to be constructed with OoD challenges in mind, and provide an extensible general framework for hard- ening diverse discriminative architectures to extreme distributional shift.