Nova Puppis 2000 (V445 Pup) is the first and so far only example of a theoretically predicted, but never before observed helium nova binary. The outburst of V445 Puppis is best modelled by a helium shell flash on the surface of a massive white dwarf primary (M > 1.33 MSun) which makes V445 Puppis a candidate supernova Ia progenitor.
We have used high-angular resolution imaging with the Very Large Telescope (using adaptive optics) to resolve the nova shell and determine the angular expansion. Combined with the expansion velocities of the shell from integral-field-unit spectroscopy on the 6.5-m Magellan telescope (resolving the shell spectroscopically on spatial scales of 0.2 arcsec), a distance estimate can be determined from the expansion parallax. Knowing the distance to V445 Pup to the best possible accuracy is essential in order to distinguish between the various models that currently exist for the parent population of helium novae.