  We present the detection of the progenitor of the Type II SN 2011dh in
archival pre-explosion Hubble Space Telescope images. Using post-explosion
Adaptive Optics imaging with Gemini NIRI+ALTAIR, the position of the SN in the
pre-explosion images was determined to within 23mas. The progenitor object was
found to be consistent with a F8 supergiant star (log L/L_{\odot}=4.92+/-0.20
and T_{eff}=6000+/-280K). Through comparison with stellar evolution tracks,
this corresponds to a single star at the end of core C-burning with an initial
mass of M_{ZAMS}=13+/-3M_{\odot}. The possibility of the progenitor source
being a cluster is rejected, on the basis of: 1) the source is not spatially
extended; 2) the absence of excess H\alpha\, emission; and 3) the poor fit to
synthetic cluster SEDs. It is unclear if a binary companion is contributing to
the observed SED, although given the excellent correspondence of the observed
photometry to a single star SED we suggest the companion does not contribute
significantly. Early photometric and spectroscopic observations show fast
evolution similar to the transitional Type IIb SN 2008ax, and suggest that a
large amount of the progenitor's hydrogen envelope was removed before
explosion.
