Hertzsprung-Russell diagram for massive stars in the SMC. The objects of NGC 346 studied in this work are shown as diamonds. For completeness, SMC stars from Ramachandran et al. (2019) are illustrated as circles. Objects with luminosity class Vz are indicated by red colour. Solid lines are evolutionary tracks at SMC metallicity (Brott al. 2011), dotted lines are isochrones with Z = 0.002 (Georgy et al. 2013). Isochrones and evolutionary tracks are for non-rotating stars.