It's one of the season's hottest tickets and this year's Serpentine Gallery Summer Party brought out all of London's movers and shakers. Models and muses trotted along to see this year's new pavilion, which has been described as a 'psychedelic caterpillar' - groovy. Christopher Kane was on hosting duties, so it was only right that the fash-pack donned his dresses, with everyone particularly taken with Alexa Chung's cheeky naked lady frock. However, it was the Waterhouse sisters, dressed like matching nymphs, who were having the best time, running around the gardens, back and forth to the Eclipse pop-up bar, before rocking out to performers Spandau Ballet and then toddling along to the afterparty at Annabel's.. GOLD stars for enthusiasm, girls.