ORANGEBURG, S.C. - It's been written many times that Democrat Barack Obama gets a "rock star" reception. Turns out the real thing is not quite the same.

Obama got to see an actual rock star reception Tuesday night. Actually, it was for the celebrity trio of Usher, Kerry Washington and Chris Tucker, who surprised an audience at South Carolina State University by introducing the presidential candidate.

Crowd members screamed and strained metal Secret Service barricades in hope of touching the trio as they entered the sports center ahead of Obama.

"I feel like Barack Obama," said Tucker, star of the blockbuster trilogy "Rush Hour," turning the cliche on its head.

The hollering continued as Usher, a five-time Grammy winner, and Washington, whose roles include Ray Charles' wife in the biopic "Ray," reminded the mostly black audience that civil-rights pioneers fought for their right to vote.

"Listen up, guys, listen up," Usher said, trying to silence them for a serious message. He said it would be negligent and irresponsible for them not to participate in Saturday's South Carolina primary. "If you don't use your voice, you didn't make a difference," he said.

Obama got a warm welcome, although he didn't have young women blowing kisses as they did for Usher or prompt shaking and near tears as did Tucker. Usher tried to build Obama's reception by pointing to audience members who weren't clapping and waving his arms upward to encourage them, and Washington started an "Obama, Obama!" chant.

Obama tried to begin his speech as the celebrities exited behind the stage. But some audience members paid the senator no mind and rushed toward the exits to touch the stars.

"I'm going to wait until they get out of here," Obama said, cutting himself short and watching with a smile. "They might cause a riot."