Jessie J appears in a promo for this weekend’s “Saturday Night Live” alongside host Zach Galifianakis and cast member Jason Sudeikis. The British songbird doesn’t say a word, looking pretty and leaving the jokes to the comedians. But her voice will be heard loud and clear when she makes her U.S. television debut on the late-night show, performing her U.S. singles “Casualty of Love” and “Price Tag” with B.o.B.