McCain intros pop star supporter at Phoenix high school

• Slideshow: Reggaeton star Daddy Yankee endorses McCain

Republican presidential nominee John McCain is letting his opponent hold the spotlight during the Democratic National Convention, but he is not taking the week off.

The Arizona senator spoke at a Phoenix high school this morning and had kind words for Democratic nominee Barack Obama.

``I have a very honorable opponent and one who will receive the nomination of his party this week in Denver, and I look forward to the last couple of months of the campaign with him," McCain told an assembly at Central Phoenix High School, his wife Cindy's alma mater.

Voters have a clear choice, McCain said.

``There are stark differences between us, but I think all of you can be proud that, again, this country will go through the most fundamental part of democracy and that is to select the next leader of our nation."

McCain told the crowd that he had a celebrity endorsement to announce.

``One of his most famous songs, I know you're familiar with, `Gasolina.' It means... here he is, Daddy Yankee."

Screaming girls greeted Daddy Yankee, a Latin Grammy-Award winning Puerto Rican Reggaeton recording artist, whose real name is Ramon Ayala.

``Amazing. I got so nervous, my heart stopped," Margarita Munoz gushed. ``I was like -- ahhhhhhhh -- you've got to be kidding," she said, giggling.

Daddy Yankee told the students that he's behind McCain because of the Arizona senator's stance on immigration issues.

``He's been a fighter for the Hispanic community and I know that me, personally, I chose him as the best candidate because he's been a fighter for the immigration issue. So for me, he's the best guy to lead this nation."

McCain's campaign staff had set up microphones and a sound system, with the idea that the senator would take some questions from students. He did not, however. McCain was about 15 minutes late to the event in Phoenix before heading to California. He spent a long weekend away from the campaign at his ranch near Sedona.

McCain's campaign today released its second ad in two days aimed at wooing Hillary Clinton's disappointed supporters, as the Republican campaign tried to take advantage of fresh reports of friction between the Clinton and Obama camps.

The new spot stars the Democratic convention delegate who lost her slot two months ago when she said publicly she'd vote for McCain, not Obama. After the party's decision, McCain asked Debra Bartoshevich to join him on the Straight Talk Express during a campaign visit to her home state of Wisconsin.

``I'm a proud Hillary Clinton Democrat," says Bartoshevich, a nurse, in the 30-second spot. "She had the experience and judgment to be president. Now, in a first for me, I'm supporting a Republican, John McCain. A lot of Democrats will vote McCain. It's okay, really!"

The TV ads, and the campaign's "Citizens for McCain" outreach initiative to former Clinton supporters, are being joined this week by efforts on the ground, as senior McCain advisor Carly Fiorina and other top campaign officials head to Denver to recruit disaffected Democrats. The Republican National Committee, which has opened a temporary war room in Denver, has made it clear the effort is a convention priority.

"Typically when parties are split, the other one wins," RNC Chairman Mike Duncan told reporters.

McCain started a busy week, seeking to grab a slice of media attention from Obama who will claim his party's nomination.

McCain also is scheduled to travel to California to raise money and make an appearance on NBC's ``Tonight'' show before returning to Phoenix late Monday.

McCain was out of the public eye on Sunday, going to church and a baseball game before a one-hour private meeting at a Phoenix hotel, which aides described as private. They declined to identify those attending. That fueled speculation about McCain's selectionof a running mate, a decision he's scheduled to announce on Friday.