Long gamma-ray bursts (GRBs) pinpoint star-forming galaxies as they are linked to the deaths of massive stars. In most cases, these galaxies have been found to be blue, sub-luminous and of low-metallicity. However, our recent survey have demonstrated that a sizeable fraction of GRBs reside in massive, dusty and star-forming extremely red objects (EROs, (R - K)AB > 3.5). The most remarkable case is the host of GRB 080207, one of the reddest galaxies ever associated with a GRB. This discovery suggests that at least a fraction of GRB afterglows trace a subpopulation of massive starburst galaxies, which are markedly different from the most studied blue, sub-luminous and compact GRB host galaxies.