  We aim to interpret the photometric and spectroscopic variability of the
luminous blue variable supergiant HD\,50064 ($V=8.21$).CoRoT space photometry
and follow-up high-resolution spectroscopy, with a time base of 137\,d and
169\,d, respectively, was gathered, analysed and interpreted using standard
time series analysis and light curve modelling methods as well as spectral line
diagnostics.The space photometry reveals one period of 37\,d, which undergoes a
sudden amplitude change with a factor 1.6. The pulsation period is confirmed in
the spectroscopy, which additionally reveals metal line radial velocity values
differing by $\sim 30\,$km\,s$^{-1}$ depending on the spectral line and on the
epoch. We estimate \teff$\sim$13\,500\,K, \logg$\sim$1.5 from the equivalent
width of Si lines. The Balmer lines reveal that the star undergoes episodes of
changing mass loss on a time scale similar to the changes in the photometric
and spectroscopic variability, with an average value of $\log\dot{\rm
M}\simeq-5$ (in M$_\odot$\,yr$^{-1}$). We tentatively interpret the 37\,d
period as due to a strange mode oscillation.

Solar and Stellar Astrophysics