Comic and former “SNL” writer John Mulaney premiered his Netflix kids musical special “John Mulaney & the Sack Lunch Bunch” Monday at Metrograph and told his child stars, “You are all incredibly kind and thoughtful to each other … You were so much better than any adult we dealt with at ‘Saturday Night Live.’ ”

Mulaney, who co-wrote the songs with “SNL’s” Marika Sawyer, revealed that the musical director took “voice memos of us singing along to already-copyrighted songs and turned them into original melodies.”

Guest stars David Byrne and André De Shields attended. Pete Davidson rolled in solo and ducked out before the after-party.