  We introduce the first g-mode pulsator found to reside on the classical blue
horizontal branch. We extend the original discovery dataset to include more
than 3 years of continuous photometry of KIC 1718290, which reveals a rich
spectrum of low-amplitude modes with periods between one and twelve hours, most
of which follow a regular spacing of 276.3 s. This mode structure strongly
resembles that of the V1093 Her pulsators, with only a slight shift towards
longer periods. Our spectroscopy, however, reveals KIC 1718290 to be quite
distinct from the sdB stars that show V1093Her pulsations, which all have
surface gravities higher than log g = 5.1 and helium abundances depleted by at
least an order of magnitude relative to the solar composition. We find that KIC
1718290 has T_eff = 22 100 K, log g = 4.72, and a supersolar helium abundance
(log He/H = -0.45). This places it well above the extreme horizontal branch,
and rather on the very blue end of the classical horizontal branch. We conclude
that KIC 1718290 must have suffered extreme mass loss during its first giant
stage, but not sufficient to reach the extreme horizontal branch.
