Shawn Mendes began his and Camila Cabello's first Valentine's Day with a big, grand gesture—the kind you'd expect from a couple young, rich, in love, and happy to show it.Mendes flew to England so he could spend the day with Cabello, who's filming Sony's new Cinderella film in London. She's playing Cinderella so, naturally, Mendes was a real Prince Charming during his visit.