  We have carried out photometry of the microlensing event MACHO-LMC-5 with
Spitzer's IRAC ten years after the magnification of the LMC source star was
recorded. This event is unique in the annals of gravitational microlensing: the
lensing star itself has been observed using HST (once with WFPC2 and twice with
ACS/HRC). Since the separation between the source and lens at the epoch of the
Spitzer observations was $\sim0.24''$, the two stars cannot be resolved in the
Spitzer images. However, the IRAC photometry clearly establishes that the lens
is a M5 dwarf star from its infrared excess, which in turn yields a mass of
$\sim0.2 M_{\odot}$. This demonstrates the potential of Spitzer to detect the
lenses in other gravitational microlensing events.
