Real-time soft-tissue simulation has gained great interest recently as a result of advancements in areas such as surgery planning and surgical simulations. Linear deformation models may not provide the required accuracy in such areas whilst non-linear models do not serve the real-time needs. Therefore, there is a common need for a computationally simplified yet accurate, non-linear, large deformable viscoelastic model of soft tissues to be used in these real-time applications. To date, standard non-linear finite-element methods are incapable of providing the real-time performance needs. Addressing this we propose a new hybrid technique that acts on the reduced order static model acquired through the model reduction technique known as Karhunen-Loeve (KL). The dynamic behavior is then obtained by overlaying pre-calculated displacement responses of surface nodes accounting for the time-dependent viscoelastic properties. The results of deformation simulation of viscoelastic soft tissue are compared with the linear approach.