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.