  DP-coloring (also known as correspondence coloring) is a generalization of
list coloring introduced by Dvo\u{r}\'{a}k and Postle (2017). Recently, Huang
et al. [https://doi.org/10.1016/j.amc.2019.124562] showed that planar graphs
with diameter at most two are $4$-choosable. In this paper, we will prove that
planar graphs with diameter at most two are DP-$4$-colorable, which is an
extension of the above result.
