  We present a first, consistent combination of measurements from top-quark and
$B$ physics to constrain top-quark properties within the Standard Model
Effective Field Theory (SMEFT). We demonstrate the feasibility and benefits of
this approach and detail the ingredients required for a proper combination of
observables from different energy scales. Specifically, we employ measurements
of the $t\bar t\gamma$ cross section together with measurements of the $\bar
B\rightarrow X_s\gamma$ branching fraction to test the Standard Model and look
for new physics contributions to the couplings of the top quark to the gauge
bosons within SMEFT. We perform fits of three Wilson coefficients of
dimension-six operators considering only the individual observables as well as
their combination to demonstrate how the complementarity between top-quark and
$B$ physics observables allows to resolve ambiguities and significantly
improves the constraints on the Wilson coefficients. No significant deviation
from the Standard Model is found with present data.
