Kate Moss can’t resist breaking into song since she formed a five-piece band with her guitarist husband, Jamie Hince of “The Kills.” After dinner at Jean-Georges Vongerichten‘s Spice Market at W Doha in Qatar Tuesday night, the supermodel joined in with jazz legend Doctor Gabs‘ show. “Kate hopped onstage and surprised diners with a rendition of the Gershwins’ ‘Summertime,’ ” our source said. “The crowd gave her a huge round of applause.” Moss, en route to the Maldives for vacation, stayed until midnight.