Paramore's Hayley Williams joined Swift to perform Speak Now (Taylor's Version)'s "Castles Crumbling" on Saturday. On Sunday, Swift and Gracie Abrams teamed up for the live debut of their ...

“London, we are so lucky because when I asked Hayley Williams to come to this show, she said yes…” Watch Taylor Swift perform Castles Crumbling with the Paramore singer for the first time.