DMX -- Ruff Ryders Are REUNITING!!!

It's official ... DMX and his legendary rap crew Ruff Ryders are getting back together -- in fact, X tells TMZ, a blowout reunion tour is already in the works.

Ruff Ryders first lady Eve told us this weekend to expect a massive comeback -- but X says the RR reunion is already underway ... with CEO Waah Dean currently booking several venues across the country.

The tour is supposed to kick off in a few months -- and X tells us, the entire crew's already on board, including Swizz Beats, Drag-On, and Murda-Mook.

According to DMX, Eve and The L.O.X. haven't signed on yet -- but that's just because he hasn't gotten in touch with them yet. X insists, that will change very soon.