As controversy swirls around a new documentary about Venus and Serena Williams on the eve of Wimbledon, Serena calmly co-hosted a pre-tournament party with fellow tennis stars Maria Sharapova, Laura Robson and Heather Watson for the Women’s Tennis Association on Thursday night. Richard Branson co-hosted the London bash at the Roof Gardens in Kensington for the WTA’s 40th anniversary. Guests included Prince Harry’s gal pal Cressida Bonas, Brit model Jade Parfitt, Bianca Jagger, designers Henry Holland and Jasmine Guinness and London party promoter Henry Conway. Earlier this week, “Venus and Serena” coincidentally premiered in London, even while its filmmakers are being sued in federal court by the United States Tennis Association for using what it claims is unlicensed footage. Directors Maiken Baird and Michelle Major said in an introduction at the Curzon Mayfair Cinema, “The USTA is trying to censor and stop the exhibition of this film about two of the greatest Americans to ever play tennis.”