  T-duality has been shown to arise from a gauge symmetry in some string
theories. However, in the case of \IIA\ compactified on a circle, it is not
possible to show that this is the case. This situation is rather uncomfortable
since string string duality suggests that all T-dualities should arise from a
gauge symmetry. Here we show that the T-duality of \IIA\ compactified on a
circle arises from the reparametrization of the supermembrane. Then we show how
this reparametrization can be understood in terms of a gauge symmetry of the
supermembrane, thus allowing to connect T-duality in \II\ to a gauge symmetry
of the supermembrane.
