  We present the analysis of phase-resolved X-ray and optical observations of
the peculiar hot star HD191612 (Of?p). This star is known to display
line-profile variations that are recurrent with a period of 538d and its
spectrum was found to present the signature of a magnetic field. In the X-rays,
it is slightly overluminous compared to the canonical L_X/L_BOL relation and
appears brighter when the optical lines are strongest. Our XMM-Newton
observations further reveal that the X-ray spectrum of \hd exhibits rather
broad lines and is dominated by a `cool' (0.2-0.6 keV) thermal component, two
characteristics at odds with the proposed magnetic rotator model. We also
report for the first time the low-level variability of the metallic (abs/em)
lines and HeII absorptions that appear to be associated with radial-velocity
shifts. Finally, we compare our results with observations of the early-type
stars and discuss several possible scenarios.
