  Using the approach based on conformal symmetry we calculate the two-loop
coefficient function for the vector flavor-nonsinglet contribution to
deeply-virtual Compton scattering (DVCS). The analytic expression for the
coefficient function in momentum fraction space is presented in the
$\overline{\text{MS}}$ scheme. The corresponding next-to-next-to-leading order
correction to the Compton form factor $\mathcal{H}$ for a simple model of the
generalized parton distribution appears to be rather large: a factor two
smaller than the next-to-leading order correction, approximately $\sim 10$\% of
the tree level result in the bulk of the kinematic range, for $Q^2=4$ GeV$^2$.
