A hydraulic actuator for a combined rear-front braking system of a motorcycle, the actuator comprising: an actuator body having an axially extending through cavity ; at least one hydraulic chamber within the actuator body ; an inlet duct in fluid communication with the hydraulic chamber , for letting a brake fluid into the hydraulic chamber ; a delivery duct in fluid communication with the hydraulic chamber , for sending brake fluid from the hydraulic chamber to a front hydraulic brake of the motorcycle; a tubular piston mounted coaxially slidable in the through cavity of the actuator body , the tubular piston being at least partially inserted into the hydraulic chamber , and having an axially extending through cavity for the passage of a mechanical cable (C) for actuating a rear brake of the motorcycle; wherein the actuator body comprises a main body of overall tubular shape, associated with a complementary body of substantially tubular shape; wherein the hydraulic actuator comprises: an outer portion of the main body ; characterised in that the hydraulic actuator further comprises: a radially inner tubular end portion of the main body extending inside the outer portion coaxial with the tubular piston ; a transversal wall of the main body connecting the outer portion to the radially inner tubular end portion ; wherein the hydraulic chamber is formed between said outer portion , said radially inner tubular end portion and said transversal wall . an actuator body having an axially extending through cavity ; at least one hydraulic chamber within the actuator body ; an inlet duct in fluid communication with the hydraulic chamber , for letting a brake fluid into the hydraulic chamber ; a delivery duct in fluid communication with the hydraulic chamber , for sending brake fluid from the hydraulic chamber to a front hydraulic brake of the motorcycle; a tubular piston mounted coaxially slidable in the through cavity of the actuator body , the tubular piston being at least partially inserted into the hydraulic chamber , and having an axially extending through cavity for the passage of a mechanical cable (C) for actuating a rear brake of the motorcycle; wherein the actuator body comprises a main body of overall tubular shape, associated with a complementary body of substantially tubular shape; wherein the hydraulic actuator comprises: an outer portion of the main body ; characterised in that the hydraulic actuator further comprises: a radially inner tubular end portion of the main body extending inside the outer portion coaxial with the tubular piston ; a transversal wall of the main body connecting the outer portion to the radially inner tubular end portion ; wherein the hydraulic chamber is formed between said outer portion , said radially inner tubular end portion and said transversal wall . an outer portion of the main body ; characterised in that the hydraulic actuator further comprises: a radially inner tubular end portion of the main body extending inside the outer portion coaxial with the tubular piston ; a transversal wall of the main body connecting the outer portion to the radially inner tubular end portion ; wherein the hydraulic chamber is formed between said outer portion , said radially inner tubular end portion and said transversal wall . a radially inner tubular end portion of the main body extending inside the outer portion coaxial with the tubular piston ; a transversal wall of the main body connecting the outer portion to the radially inner tubular end portion ; wherein the hydraulic chamber is formed between said outer portion , said radially inner tubular end portion and said transversal wall . <EOS>