  The homogeneous inviscid Burgers equation which determines the spectrum of a
TTbar deformed model has a natural interpretation as the condition of the gauge
invariance of the target space-time energy and momentum of a (non-critical)
string theory quantised in a generalised uniform light-cone gauge which depends
on the deformation parameter. As a simple application of the light-cone gauge
interpretation we derive the TTbar deformed Lagrangian for a system of any
number of scalars, fermions and chiral bosons with an arbitrary potential. We
find that the TTbar deformation is driven by the canonical Noether
stress-energy tensor but not the covariant one.
