A medicament delivery device comprising an actuator device and a container holder assembly , the actuator device comprising a housing part , the container holder assembly comprising a container holder and a needle assembly , wherein the container holder comprises: - a distal tubular body for receiving a multi-chamber container therein, the distal tubular body comprising an external surface and a distal body engaging structure on the external surface configured to movably engage the housing part in order to releasably connect the container holder to the actuator device , the container holder being manually rotatable relatively to the housing part and thereby moveable into the housing part in distal direction from a first position towards at least a second position, a movement from the first position to the second position causing the medicament inside the multi-chamber container to mix; and - a proximal tubular part comprising a proximal body engaging structure connected to the needle assembly , wherein the needle assembly is pre-assembled to the container holder before the multi-chamber container is received in the distal tubular body ; wherein the needle assembly comprises: - a hub having an injection needle with a distal needle end and a proximal needle end , the distal needle end being isolated from the multi-chamber container when the multi-chamber container is received in the distal tubular body , the distal needle end being separated from the multi-chamber container by means of a membrane and a barrier - a cap removably attached to the container holder , a manual rotation of the cap causing the hub to move distally, thereby causing the distal needle end to pierce the membrane and the barrier . - a distal tubular body for receiving a multi-chamber container therein, the distal tubular body comprising an external surface and a distal body engaging structure on the external surface configured to movably engage the housing part in order to releasably connect the container holder to the actuator device , the container holder being manually rotatable relatively to the housing part and thereby moveable into the housing part in distal direction from a first position towards at least a second position, a movement from the first position to the second position causing the medicament inside the multi-chamber container to mix; and - a proximal tubular part comprising a proximal body engaging structure connected to the needle assembly , wherein the needle assembly is pre-assembled to the container holder before the multi-chamber container is received in the distal tubular body ; wherein the needle assembly comprises: - a hub having an injection needle with a distal needle end and a proximal needle end , the distal needle end being isolated from the multi-chamber container when the multi-chamber container is received in the distal tubular body , the distal needle end being separated from the multi-chamber container by means of a membrane and a barrier - a cap removably attached to the container holder , a manual rotation of the cap causing the hub to move distally, thereby causing the distal needle end to pierce the membrane and the barrier . - a hub having an injection needle with a distal needle end and a proximal needle end , the distal needle end being isolated from the multi-chamber container when the multi-chamber container is received in the distal tubular body , the distal needle end being separated from the multi-chamber container by means of a membrane and a barrier - a cap removably attached to the container holder , a manual rotation of the cap causing the hub to move distally, thereby causing the distal needle end to pierce the membrane and the barrier . <EOS>