2MASS J20395358+4222505 is a highly extincted (Av= 9.6 mag) early B-supergiant located in the nearest massive star forming region, Cyg-X, in the outskirts of the massive star association Cyg OB2. A mass of M= 46 M$_\odot$ and a luminosity of log(L/L$_\odot$)= 5.7 make it one of the most massive and luminous stars in the Milky Way. Interestingly, the star seems to be in a transition stage, in the way to become one of the few (half a dozen) early-type hypergiants in the Galaxy. Moreover, the star is orbiting an unknown companion, with a semi-amplitude of the radial velocity curve of $\sim$100 km/s. We especulate about the possibility that the unseen companion is a compact object, a back hole of $\sim$18 M$_\odot$, or a fast rotating main sequence star of that mass.