  We present intensity interferometry of the luminous blue variable P Cyg in
the light of its H$\alpha$ emission performed with 1\,m-class telescopes. We
compare the measured visibility points to synthesized interferometric data
based on the CMFGEN physical modeling of a high-resolution spectrum of P Cyg
recorded almost simultaneously with our interferometry data. Tuning the stellar
parameters of P Cyg and its H$\alpha$ linear diameter we estimate the distance
of P Cyg as $1.56\pm0.25$~kpc, which is compatible within $1\sigma$ with
$1.36\pm0.24$~kpc reported by the Gaia DR2 catalogue of parallaxes recently
published. Both values are significantly smaller than the canonic value of
$1.80\pm0.10$~kpc usually adopted in literature. Our method used to calibrate
the distance of P Cyg can apply to very massive and luminous stars both in our
galaxy and neighbour galaxies and can improve the so-called Wind-Momentum
Luminosity relation that potentially applies to calibrate cosmological candles
in the local Universe.
