5 hours ago Mark Savage Music correspondent Samir Hussein Rosalía is playing to 40,000 fans over two nights at London's O2 Arena At one point during the first UK date of Rosalía's jaw-dropping Lux tour, the Spanish star recalled her childhood ambition of playing a show in London. "When I was studying music in Barcelona, I always dreamt of singing in one very specific place," she told fans at the O2 Arena, before adding, with perfect comic timing: "And that place is the Royal Albert Hall. "I would say it constantly to myself," she continued. "The Royal Albert Hall, the Royal Albert Hall, the Royal Albert Hall... "And I never did it. But now I've sold out the O2 twice. God bless London!" It was a tiny detail in a massive show. But it drove home the unlikely phenomenon of Rosalía's emergence as a global pop star.…