It was a fun-filled Saturday near San Francisco for a group of A-list celebrities who came together to celebrate the 40th birthday of producer Susan Downey, wife of Robert Downey Jr. Stars like Gwyneth Paltrow, Jason Bateman, Justin Theroux, and Gwen Stefani were all on hand to ring in Susan's big day at a picturesque picnic spot by the bay. The pals mixed and mingled at a food truck as their kids played in the grass. Gwyneth Paltrow shared a sweet hug with her daughter, Apple Martin, while actress Maya Rudolph brought along her 3-year-old daughter, Lucille, and the baby daughter she welcomed in September. Justin Theroux, who showed up sans fiancée Jennifer Aniston, stayed close to Jason Bateman, and Jason even helped feed Justin a sandwich while they chatted. Gwen Stefani, who is currently pregnant with her third child, gushed over another partygoer's baby while her husband, Gavin Rossdale, socialized with the crowd.
Reese Witherspoon and her family were also on hand for the event; she showed up with her husband, Jim Toth, and kids Ava and Tennessee and seemed to be enjoying herself while eating snacks and snapping photos. Reese and 14-year-old Ava even posed for their own mother-daughter photo — can you believe how much they look alike? Everyone at the outdoor gathering looked to be having a blast — maybe Susan Downey can produce them all in a movie together?