Abstract: The watch assembly comprises a case housing the watch mechanism and the display screen, actuator means for actuating the mechanism external to the case and connected to the mechanism by connection means, and a wristlet supporting the actuator means, the connection means, and the case, which case is placed on the back of the hand. The wristlet comprises a flexible piece comprising: a) a proximal portion for surrounding the wrist; b) a distal portion for surrounding at least the first phalanx at the base of the index finger; and c) an intermediate portion for extending over the back of the hand between said proximal and distal portions and supporting the case. At least one actuator means is mounted laterally on the distal portion of the wristlet so as to be actuatable by the thumb of the same hand.