  We present a joint extraction of the strong coupling $\alpha_s$ and the
top-quark pole mass $m_t$ from measurements of top-quark pair production
performed by the ATLAS and CMS experiments at the 8 TeV LHC. For the first
time, differential NNLO theory predictions for different values of the
top-quark mass are utilised for four kinematic distributions: the average
transverse momentum of the top-quark, its average rapidity and the pair
invariant mass and rapidity. The use of fastNLO tables for these distributions
allows rapid evaluation of the differential theory predictions for different
PDF sets. We consider the single differential distributions from the
experiments both separately and in combination in order to obtain the best fit
to theory. Our final values are $\alpha_s=0.1159^{+0.0013}_{-0.0014}$ and
$m_t=173.8^{+0.8}_{-0.8}$ GeV which are compatible with previous extractions
using top-quark measurements. In the case of $m_t$, our value is also
compatible with the world average value collated by the Particle Data Group.
