Watch 'Argylle' Cast React to Taylor Swift Fan Theory Behind Book (Exclusive)

'Argylle' director Matthew Vaughn and stars Samuel L. Jackson, Ariana DeBose, John Cena, Bryce Dallas Howard, Bryan Cranston, Henry Cavill and Sam Rockwell chat with ET's Nischelle Turner in London about a fan theory that says Taylor Swift's the secret author behind the book that inspired the movie. Matthew debunks the theory, while the cast members share whether they've met the mysterious author and if they're Swifties. 'Argylle' hits theaters on Feb. 2.