  We propose helioseismology as a new, precision probe of fifth forces at
astrophysical scales, and apply it on the most general scalar-tensor theories
for dark energy, known as Degenerate Higher-Order Scalar-Tensor theories
(DHOST). We explain how the effect of the fifth force on the solar interior
leaves an observable imprint on the acoustic oscillations, and under certain
assumptions we numerically compute the non-radial pulsation eigenfrequencies
within modified gravity. We illustrate its constraining power by showing that
helioseismic observations have the potential to improve constraints on the
strength of the fifth force by more than $2$ orders of magnitude, as $-1.8
\cdot 10^{-3} \leq Y \leq 1.2 \cdot 10^{-3}$ (at $2\sigma$). This in turn would
suggest constraints of similar order for the theory's free functions around a
cosmological background ($\alpha_{\text{H}}, \beta_{1}$).
