We discuss the origin of the early-B-type runaway star HD 271791 and show that its extremely high velocity (≃530 − 920km s−1) cannot be explained within the framework of the binary–supernova ejection scenario. Instead, we suggest that HD 271791 attained its peculiar velocity in the course of a strong dynamical encounter between two hard, massive binaries or through an exchange encounter between a hard, massive binary and a very massive star, formed through runaway mergers of ordinary massive stars in the dense core of a young massive star cluster.
