Gwyneth PaltrowEugene Gologursky/WireImage for InStyle

Gwyneth Paltrow (in vintage Calvin Klein) helped Jessica Seinfeld (in Reed Krakoff) celebrate the 10th anniversary of Baby Buggy—a non-profit organization that provides clothing, diapers and other infant essentials to families in need—during an elegant outdoor dinner in East Hampton. “I didn’t realize how relentless it would be,” Paltrow said of her own motherhood experience. “Or how much I would love my children.” Click through the gallery to see Jessica Alba, Angelina Jolie and more stars at this weekend’s hottest events!