  The spectral excess theorem for distance-regular graphs states that a regular
(connected) graph is distance-regular if and only if its spectral-excess equals
its average excess. A bipartite graph is distance-biregular when it is
distance-regular around each vertex and the intersection array only depends on
the stable set such a vertex belongs to. In this note we derive a new version
of the spectral excess theorem for bipartite distance-biregular graphs.
