Well, sort of . . . yes, they are singing like cats, but only as part of Denise Lane’s senior recital (she’s the one wearing the blue dress). Nijmeh Rapp (in the red dress) joined her in their rendition of Rossini’s Duetto Buffo Di Due Gatti which probably means something like Duet of the Buff Kitties (okay, I’m not fluent in Italian, but I figured I’m allowed at least one guess . . .)
In any event, check out the attached video. Not just anyone can sing this and pull it off—it has to be performed with maximum ATTITUDE!