  We consider general planar deformations of a circular distribution of
NS5-branes. The near-horizon region of the latter admits, after a T-duality
transformation, an exact conformal-field-theory description in terms of the
coset model SU(2)/U(1) X SL(2,R)/U(1). We derive the exactly marginal operators
corresponding to an infinitesimal planar deformation using the conjectured
holography between the coset model and the little string theory that resides on
the worldvolume of the NS5-branes. Subsequently, we perform a complementary
analysis of the same deformations using the associated N=1 supersymmetric sigma
model and verify the holographic correspondence. We explicitly demonstrate a
precise match between the two approaches which rests upon a delicate interplay
between exact conformal-field-theory operators and their semiclassical
realizations in terms of target-space variables.
