Gwen Stefani bundled up Kingston Rossdale and Zuma Rossdale for a trip to the aquarium today in London. The trio have been hanging out in England lately, while Gavin Rossdale tours with Bush, and have gone on several mommy-and-me outings to the zoo and local parks. The Stefani-Rossdales also had a playdate with the Jolie-Pitts late last month. Gwen may be focusing on time with her boys lately, but she's also hit the town for some adults-only events. A few days ago, she joined Kate Winslet at the launch party for a new cookbook, and last night she stepped out to celebrate Stella McCartney's second 40th birthday with famous friends like Cameron Diaz and Kate Moss.