  We present an experiment of nonclassical interference between a pure heralded
single-photon state and a weak coherent state. Our experiment is the first to
demonstrate that spectrally pure single photons can have high interference
visibility, 89.4 \pm 0.5%, with weak coherent photons. Our scheme lays the
groundwork for future experiments requiring quantum interference between
photons in nonclassical states and those in coherent states.
