The various sub-systems of PRIMA, the Phase-Referenced Imaging and Micro-arcsecond Astrometric facility for the Very Large Telescope Interferometer, are nearly completed and are in the process of being tested individually and as a full system. The VLTI is being prepared to receive this important enhancement in 2007. We hope to offer this facility to the community in 2008. The various scientific objectives of PRIMA will be recalled. Faint object imaging with an increase of the VLTI limiting magnitude by several magnitudes should be possible if a proper bright reference source can be found close by, increasing signitifcantly the number of extra-galactic targets accessible to the VLTI. Differential phase (with respect to a reference object) will also give additional imaging information on circum-stellar matter, galaxy dust tori, PRIMA being complementary to the phase-closure technique. Finally, narrow angle astrometry will be possible with a very high accuracy allowing studies of extra-solar planets and micro-gravitational lensing among others. The status of the various sub-systems as well as the results of their tests will be presented. The global performances that we hope to reach with PRIMA in Paranal will be extrapolated.