Saturday night at Festival Supreme in Los Angeles, Amy Poehler and Jack Black joined forces to perform a soul-searing cover of Bette Midler’s “The Rose.†Poehler, decked in Janis Joplin–inspired garb and holding a cigarette, previously showed off some musical chops in a Golden Globes promo from 2013, and Black’s ability to belt out a tune is no secret, but they come together with surprising tenderness here.