A thermally and electrically controllable miniaturised actuator comprises a bi-layer structure formed of a shape-memory alloy layer coupled with an electro-active polymer layer. A heating means is provided for thermal stimulation of the shape-memory alloy layer, this layer transitioning from an initial shape at a first temperature to a second, pre-determined, shape at a second temperature. Application of an electric field to the electro-active polymer layer stimulates this layer to deform in response, with a stress which may exceed that of the alloy layer, when the latter layer is in a low-temperature phase. Actuation methods are further provided, which include stimulating the polymer layer to deform in an opposite ‘direction’ to the deformation of the alloy layer, thus allowing the actuator to be ‘reset’ in between strokes. Methods of producing an actuator are also provided.