Positions of the LMC (red filled circles) and SMC (blue filled squares) post-RGB candidates on the HR diagram. The main-sequence is represented as a cyan and grey cross-hatched region. The black solid lines represent evolutionary tracks starting from the main sequence and continuing up to the AGB-tip with an initial composition Y = 0.23, Z = 0.004 (Bertelli et al. 2008, 2009). The black dotted lines represent PMS evolutionary tracks for an initial composition Y = 0.238, Z = 0.004 (Tognelli et al. 2011). The masses of the evolutionary tracks are indicated in the plots, with the pre-main-sequence and main-sequence masses shown on the left side of the main-sequence band and the RGB-tip masses on the right side of the plots. The black dashed arrows schematically represent the post-AGB and post-RGB evolutionary tracks (the masses of the post-AGB and post-RGB stars are given at the arrow ends). The masses for the post-AGB evolutionary tracks are taken fromVassiliadis & Wood (1994). The post-RGB evolutionary track masses are estimated from the RGB luminosity-core mass relation obtained from fits to the evolutionary tracks of Bertelli et al. (2008).