Abstract: A data processing apparatus and method are provided for controlling level shifting. The data processing apparatus comprises a first component provided within a first voltage domain and operable to receive. a first supply voltage, and a second component provided within a second voltage domain and operable to receive a second supply voltage. At least one of the first and second supply voltages are dynamically variable. The data processing apparatus further comprises an interface cell between the first and second voltage domains which is operable to receive a signal issued by the first component in the first voltage domain and destined for the second component. The interface cell comprises level shifting logic operable to convert the signal issued by the first component into a corresponding signal to be propagated to the second component in the second voltage domain.