  We formulate the dynamics for the NS5-brane of the A-model, via the 'maximal
form' method, which couples all background fields to the world-volume. This
procedure provides the extra one- and five-forms fields of the extended Hitchin
model. The generalised B-model emerges as the world-volume theory of this
brane. The starting point of the construction is an embedding of the brane in a
superspace geometry with 16 fermionic directions. The correspondence with
Hitchin's formulation in terms of pure spinors is explained.
