Cyrus picks up some school supplies at an Office Depot in Los Angeles. Plus: Jessica Simpson, Nicole Richie and Jay-Z, Matt Damon and more

REVEL WITH A CAUSE

It's Matt in the middle! Proud dad Matt Damon joins members of the African Children's Choir Monday at the OneXOne charity gala in Toronto, Canada. The actor, who hosted the event to fight child poverty, told PEOPLE that almost-3-week-old daughter Gia Zavala is already smiling.