Watch comprising a transmission device between a control member and the movement

A watch comprising a case having a middle part and inside which is housed a movement, the watch including a control member intended to be actuated by a user, the watch further comprising an internal transmission device provided with an actuator able to move, in response to actuation of the control member, between a rest position and an active position in which the actuator actuates a mechanism of the movement, wherein the transmission device includes a closed cavity filled with a fluid and a thrust means kinematically connected to the control member and arranged to displace the fluid inside the cavity, wherein the displacement of fluid inside the cavity causes displacement of the actuator, and wherein the thrust means is a control piston and in that the actuator includes an actuator piston.