Left: bolometric light curve computed with HERACLES for models RE0p4B3p5 (RSG progenitor) and BE0p4B3p5 (BSG progenitor) under the influence of a magnetar (thick line) or not (thick dashed line). The thin dashed line corresponds to the magnetar power at >250 d. Prior to theinfluence of magnetar power on the emergent light, the luminosity stems primarily from shock deposited energy. It is at such early times that one may distinguish a BSG from a RSG star as the progenitor of a super-luminous SN. Right: maximum light spectra (around 100 d after explosion) for the two models shown at left.