NEW YORK — Gwyneth Paltrow threw a star-studded bash for her son Moses' seventh birthday on April 8. Paltrow, who recently released her new healthy book and launched her fourth fitness studio with exercise expert Tracy Anderson in Los Angeles this week, and her husband Chris Martin were joined by Kate Hudson, Tobey Maguire, Cameron Diaz, Gwen Stefani and Joel Madden, as well as all their children, at their new mansion in Brentwood, California. Martin was walking around the party barefoot, totally relaxed and having a good time. He spent a lot of time sitting with Maria Shriver and her kids chatting. Everyone was dressed casually in summer clothes and sunglasses. It looked like a relaxed atmosphere where they could show off their new house and celebrate their son's birthday. People stayed all day and really enjoyed themselves, ndtv.com reported. The celebrity children spent the day playing with hula-hoops, table top football, basketball and dancing on the lawn in the middle of the property. Paltrow also put aside her strict gluten-free, low-carb diet and treated the guests to hamburgers, fries and several different types of salad. — SG