It is argued that the existence of constant dilaton field solutions is a
generic feature of string-inspired dilaton gravity. Such solutins arise in the
extreme limit of black hole metrics. It is shown that in a strong coupling
region quantum effects give rise to two horizons in thermal equilibrium that
has no classical counterpart.Comment: 7 pages, REVTeX, no figures. Minor corrections in presentation. To be
published in Phys. Lett.
