  Exciton condensates (EC) are macroscopic coherent states arising from
condensation of electron-hole pairs. Bilayer heterostructures, consisting of
two-dimensional electron and hole layers separated by a tunnel barrier, provide
a versatile platform to realize and study EC. The tunnel barrier suppresses
recombination yielding long-lived excitons. However, this separation also
reduces interlayer Coulomb interactions, limiting the exciton binding strength.
Here, we report the observation of EC in naturally occurring 2H-stacked bilayer
WSe$_2$. In this system, the intrinsic spin-valley structure suppresses
interlayer tunneling even when the separation is reduced to the atomic limit,
providing access to a previously unattainable regime of strong interlayer
coupling. Using capacitance spectroscopy, we investigate magneto-EC, formed
when partially filled Landau levels (LL) couple between the layers. We find
that the strong-coupling EC show dramatically different behaviour compared with
previous reports, including an unanticipated variation of the EC robustness
with the orbital number, and find evidence for a transition between two types
of low-energy charged excitations. Our results provide a demonstration of
tuning EC properties by varying the constituent single-particle wavefunctions.
