HIZSS3 is an H I source in the Zone of Avoidance .
Its radio characteristics are consistent with it being a previously unknown nearby ( \sim 1.8 Mpc ) low-mass dwarf irregular ( dIm ) galaxy .
Optical observations have shown that it contains a modest H II region but failed to reveal a resolved stellar population .
New spectroscopic observations of the H II region obtained at the MMT Observatory are presented here .
They are used to derive the line-of-sight extinction ( E ( B - V ) = 1.41 \pm 0.04 ) and gas metallicity ( log O / H + 12 \sim 7.8 ) of the H II region .
New near-IR imaging observations obtained at the ESO Very Large Telescope are also presented here .
These images clearly reveal the resolved stellar population of HIZSS3 for the first time .
Narrow-band P \beta images of the H II region are used in combination with previously published H \alpha data to obtain an independent line-of-sight extinction estimate : E ( B - V ) = 1.32 \pm 0.04 .
The adopted foreground extinction is E ( B - V ) = 1.36 \pm 0.06 .
Based on the K-band luminosity function and K,J - K color-magnitude diagram , the apparent magnitude and color of the tip of the red-giant branch ( TRGB ) are derived .
In turn , these parameters are combined with the adopted foreground extinction to estimate the distance ( 1.69 \pm 0.07 Mpc ) and mean red giant branch metallicity ( [ Fe / H ] = -0.5 \pm 0.1 ) .
As an ensemble , these new observations significantly strengthen the conclusion that HIZSS3 is a newly discovered low-mass dIm lurking behind the Milky Way in the outskirts of the Local Group .