  We report the serendipitous discovery from WASP archive photometry of a
binary star in which an apparently normal A-type star (J0247-25A) eclipses a
smaller, hotter subdwarf star (J0247-25B). The kinematics of J0247-25A show
that it is a blue-straggler member of the Galactic thick-disk. We present
follow-up photometry and spectroscopy from which we derive approximate values
for the mass, radius and luminosity for J0247-25B assuming that J0247-25A has
the mass appropriate for a normal thick-disk star. We find that the properties
of J0247-25B are well matched by models for a red giant stripped of its outer
layers and currently in a shell hydrogen-burning stage. In this scenario,
J0247-25B will go on to become a low mass white dwarf (M~0.25 solar masses)
composed mostly of helium. J0247-25B can be studied in much greater detail than
the handful of pre helium white dwarfs (pre-He-WD) identified to-date. These
results have been published by Maxted et al., 2011. We also present a
preliminary analysis of more recent observations of J0247-25 with the UVES
spectrograph, from which we derive much improved masses for both stars in the
binary. We find that both stars are more massive than expected and that
J0247-25A rotates sub-synchronously by a factor of about 2. We also present
lightcurves for 5 new eclipsing pre-He-WD subsequently identified from the WASP
archive photometry, 4 of which have mass estimates for the subdwarf companion
based on a pair of radial velocity measurements.
