Solution: There are five celebrity names (signatures) in the across entries and there are five words/phrases in the down entries that sound like the celebrities’ initials. 17A & 13D, 26A & 30D, 39A & 37D, 51A & 51D, 63A & 2D. The first letters of the down clues are KGNME, which sounds like the meta answer- CAGEY ENEMY