  We derive the complete set of off-shell nilpotent and absolutely
anticommuting (anti-)BRST as well as (anti-)co-BRST symmetry transformations
for the gauge-invariant Christ-Lee model by exploiting the celebrated
(dual-)horizontality conditions together with the gauge-invariant and
(anti-)co-BRST invariant restrictions within the framework of geometrical
"augmented" supervariable approach to BRST formalism. We show the (anti-) BRST
and (anti-)co-BRST invariances of the Lagrangian in the context of
supervariable approach. We also provide the geometrical origin and capture the
key properties associated with the (anti-)BRST and (anti-)co-BRST symmetry
transformations (and corresponding conserved charges) in terms of the
supervariables and Grassmannian translational generators.
