A hybrid drive assembly (1) for a vehicle having at least one drive wheel (2), the drive assembly including an internal combustion engine (3); a transmission unit (5) interposed between a drive shaft (4) of the internal combustion engine (3) and a propeller shaft (6) connected angularly to the drive wheel (2), and in turn including a continuously variable transmission (7) having a drive pulley (10) connected angularly to the drive shaft (4) and a driven pulley (11), and a centrifugal clutch (8) having a hub (20) connected to the driven pulley, and a driven bell (26) connected to the propeller shaft (6); and an electric machine (32) having a rotor (35) integral with the bell (26) of the centrifugal clutch (8). The drive assembly (1) is controlled by a control unit (38), in response to a number of input signals (Ss, Sa, Sf), in a number of operating modes including an all-combustion propulsion mode, an all-electric propulsion mode, a first hybrid propulsion mode wherein the internal combustion engine (3) and the electric machine (32) are connected in series, and a second hybrid propulsion mode wherein the internal combustion engine (3) and the electric machine (32) are connected in parallel.