Jennifer Lopez was the latest guest to join Jimmy Fallon in his "Ew!" skit on Wednesday. She made a fun appearance as Sara's BFF Gabby, who was having "the worst day ever" because her dad joined Snapchat. In efforts to cheer her up, the girls practiced their best "Snap faces" using the hilarious Snapchat filters, and then participated in a talent show. Before showcasing her talent, Jennifer admits that "she's really shy" and then completely shocks Sara when she twerks up a storm to Rihanna's new single, "Work," in her living room. Prepare to crack up and watch the clip in full above, and then check out all the celebrity guests who have been on Jimmy's "Ew" sketch.