BOSTON — John Edwards and Barack Obama took time out from the Democratic National Convention to attend a Rock the Vote concert Thursday night in Boston, and the 20-something crowd greeted the politicians like rock stars.

Democratic vice presidential candidate Edwards appeared on stage with his wife, Elizabeth, and 22-year-old daughter, Cate. He shook hands with the members of the rock band Maroon Five and gave the shrieking audience the thumbs-up sign.

Earlier in the evening, state Senator Obama made a surprise appearance, and the crowd responded by chanting his name.

He told them the concert was the only stop he planned to make before going to bed.

LL Cool J also performed at the concert. Celebrities Alyssa Milano, Leonardo DiCaprio and Ben Affleck watched from a VIP balcony.