  We present observations of the massive transitional star W243 in Westerlund
1. We find an apparent spectral type of early-mid A from our data, in contrast
to an earlier classification of B2I, made from data obtained in 1981. The
concurrent development of a rich emission line spectrum suggests a very high
mass loss rate; the continued presence of HeI emission suggesting that the
underlying star remains significantly hotter than implied by its apparent
spectral type. We suggest that W243 is a Luminous Blue Variable undergoing an
eruptive phase, leading to an extreme mass loss rate and the formation of a
pseudo photosphere.
