The disclosure relates to a cap assembly according to the present invention. The cap assembly comprises a medicament delivery device comprising a body having a proximal and a distal end. Further, the cap assembly comprises a graspable cap removably attached to the proximal end of the body. Further, the cap assembly comprises a graspable sleeve element having a proximal and a distal part, the sleeve element is arranged to at least partially enclose the body. The sleeve element is arranged to be non-removably attached to the body, but able to rotate relative to the body. The sleeve element is arranged to interact with the cap such that the cap is displaced proximally in relation to the body when the sleeve element is rotated relative to the body.