  The core helium-flash in low-mass stars with extreme mass loss occurs after
the tip of the RGB, when the H-rich envelope is very thin. The low efficiency
of the H-shell source enables the He-flash driven convective zone to penetrate
H-rich layers and trigger a thermonuclear runaway, resulting in a subsequent
surface enrichment with He and C. In this work we present the first full
computations of Population II low-mass stellar models through this phase.
Models experiencing this dredge-up event are significantly hotter than their
counterparts with H-rich envelopes, which makes them promising candidates for
explaining the existence of stars observed beyond the canonical blue end of the
horizontal branch ("blue hook stars"). Moreover, this temperature difference
could explain the observed gap in M_V between extreme blue horizontal-branch
and blue hook stars. A first comparison with spectroscopic observations of blue
hook stars in the globular cluster omega Cen is also presented.
