David Arquette has FINALLY become a man ... 'cause the 41-year-old actor just had his Bar Mitzvah in Jerusalem. L'chaim!
Arquette -- who's in Israel to film a travel show -- had been attending a separate Bar Mitzvah ceremony for a local boy, when someone suggested David should get a BM of his own.
According to VosIzNeias.com, David -- whose mother is Jewish -- liked the idea ... so he strapped on a kippah and tefillin (prayer garb) and made it happen right in front of the Western Wall.
David was later presented with a Bar Mitzvah certificate ... but as everyone knows, the occasion doesn't become official until someone puts him in a chair and hoists him around the room.