  We derive the four-dimensional integrand of the maximal-helicity-violating
four-particle form factor for the chiral part of the stress-tensor
supermultiplet in planar $\mathcal{N}=4$ super-Yang-Mills theory at two loops.
In our integrand construction, we adopt a special integrand basis with triangle
powercounting where each basis element has unit leading singularities on all
co-dimension eight residues. This basis was first constructed in the context of
two-loop $n$-point scattering amplitudes in $\mathcal{N}=4$ beyond the planar
limit and we describe here, how to directly utilize it for the form factor
computation. Our result sets the stage for an independent confirmation of the
symbol level bootstrap results of Dixon et al.~via direct evaluation. The
imminent availability of all relevant two-loop five-point, one-mass master
integrals will permit further investigations of a set of marvelous
(self-)dualities between form factors and scattering amplitudes in planar
$\mathcal{N}=4$ in the near future.
