  We construct a unique (2,0) supersymmetric action in six dimensions,
describing a tensor multiplet interacting with a self-dual string. It is a sum
of four terms: A free kinetic term for the tensor multiplet fields integrated
over Minkowski space, a Nambu-Goto type kinetic term for the string integrated
over the string world-sheet, a Wess-Zumino type electromagnetic coupling
integrated over the world-volume of a Dirac membrane attached to the string,
and a direct interaction of such Dirac membranes. In addition to supersymmetry,
the action is also invariant under a local symmetry, which allows us to choose
the Dirac membrane world-volume freely and eliminate half of the fermionic
degrees of freedom on the string world-sheet.
