  We report Johnson's UBVRI photometric and optical spectroscopic observations
of a long period variable HP Lyr which up to now has been considered an
eclipsing binary with a period of 140 days. The spectral type changes
continually from A2-3 at maxima to A7-F2 at minima. We propose that the
brightness changes are caused by the pulsation of the star with two periods:
P1=69.35, and P2=2xP1=138.7 days. These periods decreased by more than 1%
between 1960 and 1980. The spectral luminosity class determination gives an A
type supergiant Iab. HP Lyr is also the optical counterpart of the infrared
source IRAS 19199+3950. Relatively high galactic latitude (b=+11.7 degr) and
high radial velocity (-113 km/s) indicate that HP Lyr is an evolved, most
likely post-AGB star. All presented features argue that this star is an RV Tau
type object.
