We present photometric and spectroscopic optical and near-infrared (NIR) ob
servations taken during the outburst on September 1999 of the source V4641
Sgr=SAX J1819.3-2525 (in't Zand et al., 2000) = XTE J1819-254 (Markwardt et
al., 1999). We show that our observations suggest a distance between 4 and
8 kpc, the spectral type of the companion star being constrained between B
3 and A2 V, making the system a High Mass X-ray Binary System (HMXB). In vi
ew of the radio and optical/NIR observations, it is possible that the eject
a of the source interacted with the surrounding medium of the source.