After entertaining Gleeks across the United States, Darren Criss and Dianna Agron crossed the pond to London for the European leg of their Glee Live! tour. The duo jammed inside the VIP tent at the Hard Rock Calling music festival before rejoining co-stars Cory Monteith, Lea Michele and Heather Morris to perform for their British fans. "Can't believe the events that have happened in 24 hours. Last night, the Killers in Hyde park, today, playing two shows at the O2," Agron Tweeted. Click through the gallery to see Heidi Klum, Kim Kardashian, Rosie Huntington-Whiteley and more stars at this weekend’s hottest parties!