  We propose a mechanism that couples matter fields to three-dimensional
quantum gravity, which can be used for theories with a positive or negative
cosmological constant. Our proposal is rooted in the Chern-Simons formulation
of three-dimensional gravity and makes use of the Wilson spool, a collection of
Wilson loops winding around closed paths of the background. We show that the
Wilson spool correctly reproduces the one-loop determinant of a free massive
scalar field on rotating black holes in AdS$_3$ and Euclidean dS$_3$ as $G_N\to
0$. Moreover, we describe how to incorporate quantum metric fluctuations into
this formalism.
