Stella McCartney had a 40th birthday party — again! — in London. Some of the same characters from her lavish first bash attended last night's at the more low-key venue of Notting Hill's Cow Pub, like Kate Moss, Jamie Hince, and Gwyneth Paltrow. There were new faces too, with Liv Tyler, Gwen Stefani, and Cameron Diaz, who watched Jude Law's Anna Christie earlier in the evening, wishing Stella well. Kate apparently went to the pub just after she returned from Paris, where she walked in Louis Vuitton's show at her own request and held a bash to celebrate her new line of jewels for Fred. Uncharacteristically, though, Kate and Jamie were reportedly among the first guests to leave. The party gave good pals Gwyneth and Cameron a chance to hang out at the relaunch of the Arts Club on Tuesday, and Paltrow hopped on stage to serenade a royal crowd that included Prince Philip.