A downhole seal system comprising at least one a deformable member; and at least one expandable seal; wherein the deformable member is provided proximate, adjacent, against, or fixed to the expandable seal. Optionally, the expandable seal is or comprises a swellable seal and/or the deformable member comprises or at least partially defines a seal receiving groove and at least part of the expandable seal is received or receivable within the seal receiving groove such that the expandable seal is expandable so as to deform the deformable member and thereby increase an outer diameter or extent of the deformable member. Also described is an associated deformable member and fixing member and associated methods for producing and using the seal system.