A surprise guest is the famous face who walks on stage unannounced during someone else’s show, turning an ordinary night into the one fans will boast about for years. Some are spontaneous; most are planned with military precision and kept quiet until the last second.
Taylor Swift’s 1989 World Tour turned the surprise guest into a nightly event during 2015. Over the run she brought out singers, athletes, models and actors, among them Serena Williams, Lorde, Gigi Hadid and Ellen DeGeneres, while Idina Menzel sang Let It Go dressed as Elsa. The moment fans still treasure came at the Staples Center in Los Angeles on 26 August 2015, when Lisa Kudrow joined her for Smelly Cat, the gloriously odd song her character Phoebe sings in Friends. Audiences spent the rest of the tour guessing who would appear next, which was rather the point.