Mel B, the former Spice Girl and a judge on “America’s Got Talent,” musician Jacob Collier, TV host Padma Lakshmi, actor Natalie Dormer, best known for “Game of Thrones,” U.K. TV hosts Ant and Dec, and Chelsea Clinton, vice chair of the Clinton Foundation, are among the latest star names to be added as speakers at SXSW London . Other new speakers announced Friday include Hasan Piker, political commentator and broadcaster, George Osborne, a former leading U.K. politician and now managing director and head of Open AI for Countries, Esther Perel, psychotherapist and author, Tim Berners-Lee, inventor of the internet and CTO and co-founder of Inrupt, Max Junestrand, CEO and co-founder of Legora, Julia Goldin, chief product and marketing officer of LEGO, and Federico Begher, global head of product at LEGO.…