Stewart Copeland, Adrian Belew, Mark King, and Vittorio Cosma. Those last two guys haven't done anything I know (Cosma was a member of PFM in the 80s which is long after I stopped paying attention to them, and Mark King played with Level 42 who I know nothing about).
But Copeland and Belew working together has a lot of interesting potential (have they worked together before? It seems likely, but I can't think of anything). And from the sound of the song they released it seems they're embracing the Italian prog side of things which is certainly an angle you don't hear too much of these days.