  We discuss the origin of the runaway early B-type star HD271791 and show that
its extremely high velocity (\simeq 530-920 km/s) cannot be explained within
the framework of the binary-supernova ejection scenario. Instead, we suggest
that HD271791 attained its peculiar velocity in the course of a strong
dynamical encounter between two hard massive binaries or via 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.
