A further benefit of dipole-dipole CCR is that it provides access to the spectral density at zero frequency, J(0), while it is immune to chemical exchange contributions, which otherwise require the additional interpretation of R 2 or R 1ρ relaxation dispersion measurements in terms of fast ("supra-τ c ") internal motions. Thus, there is easier access to methyl NMR order parameters from J(0). As has been shown, access to J(0) is vital for accurate determination of protein internal motion. Here, we provide a methodological framework for obtaining NMR cross-correlated relaxation parameters of side chain methyl groups in proteins from MD simulations. The applicability and accuracy of the approach are demonstrated for ubiquitin (UBQ), a small protein for which accurate reference data from CCR experiments are available. We build on the previous work of Hoffmann and coworkers and of Chen and coworkers, and study the overall tumbling motion in TIP4P/2005 water, in combination with the AMBER ff99SB*-ILDN and CHARMM36 protein force fields. We then report the cross-correlated relaxation rates and methyl order parameters. Our work shows that CCR provides an excellent metric for validating MD simulations in terms of internal protein dynamics. While the results display an appropriate agreement between experiments and computations, they also highlight areas where improvements can still be made.