  In this communication, we present a class of Brans-Dicke-like theories with a
universal coupling between the scalar field and the matter Lagrangian. We show
this class of theories naturally exhibits a decoupling mechanism between the
scalar field and matter. As a consequence, this coupling leads to almost the
same phenomenology as general relativity in the Solar System: the trajectories
of massive bodies and the light propagation differ from general relativity only
at the second post-Newtonian order. Deviations from general relativity are
beyond present detection capabilities. However, this class of theories predicts
a deviation of the gravitational redshift at a level detectable by the future
ACES and STE/QUEST missions.
