Bareilles performs Friday at a Las Vegas middle school, where Obama will host his latest "Moving America Forward" rally.
Nevada is prime battleground for Democrats, who face losing Senate Majority Leader Harry Reid if Republican Sharron Angle's tea party bid is successful. Republicans have painted Reid as the face of Obama's sweeping social and economic policies, including the federal health care law and the $787 billion stimulus.
Bareilles is a White House favorite. She performed before world leaders at the G-20 summit in 2009 and during the First Family's 2010 Easter Egg Roll.