Kate Hudson hopped on her bike after a workout at the Spring Health Club in London today. She wore Vibram Five Fingers barefoot shoes for the latest gym visit alongside her fiancé, Matthew Bellamy. Kate and Matthew focused on their fitness after a big night out celebrating Stella McCartney's 40th birthday yesterday. The couple were among many celebrity guests at the bash, including Gwyneth Paltrow and Kate Moss, though all eyes were on Kate Hudson in her sexy backless Elie Saab gown. She's been staying active since giving birth to Bing in July, and she's been spotted riding bikes with Matt near their London home since they relocated there last month. Kate showed off the results of her hard work in a white bikini during a recent vacation with her family in France, though Bing didn't make an appearance during the Mediterranean getaway.