A powertrain for a vehicle includes a combustion engine and a drivetrain having a coupling with a first state of operation in which the input of the coupling is locked to the output of the coupling, and a second state of operation in which the input of the coupling is not locked to the output of the coupling for allowing slippage. The drivetrain also has a final drive configured for supplying torque to a drive wheel from the coupling, wherein the final drive is coupled to the coupling at a fixed gear ratio. The powertrain further includes one or more electric motors configured to supply torque to the drivetrain one or both of the input side and the output side of the coupling.