David Arquette Signs On for "Dancing with the Stars"

David Arquette will show what he's got on "Dancing with the Stars" ... sources close to the deal tell TMZ.

David showed up to the rehearsal studio a few minutes ago, to meet his partner for the first time. We're told he's hooking up -- professionally, in a dancing sort of way -- with Kym Johnson.

The new season starts at the end of September.