Spinners and Winners

Rock 'n Roll Hall of Famer Elton John once called President George W. Bush "the worst thing that ever happened to America." But in an interview with ABC News/Yahoo! Power Players series, Sir Elton offers a different description of Bush: The U.S. President who has done most to fight AIDS.

Asked directly what President has done more than any other to combat AIDS, John answered without hesitation: "George Bush."

Elton John, who has been a leading activist on AIDS issues since the 1980s, gives President Bush credit for launching the President's Emergency Plan for AIDS Relief (PEPFAR) a $15 billion program Bush signed into law in 2004 to provide treatment and prevention for millions of HIV-infected people in Africa.

Prior to that, John had been among President Bush's harshest and most acerbic critics.

"I wasn't a big fan of his policies," John said. "I was very against the Iraq war. So, you know, his policies didn't sit well with mine."

But not long after Bush launched his anti-AIDS effort, Elton John had a chance to meet him in person. The occasion was the 2004 Kennedy Center Honors.

"At the Kennedy Center concert we spent some time in the intermission with the President, George Bush, and he was an amazingly informed about AIDS," John recounted. "He treated us with such kindness. I had so much respect for him, especially when the PEPFAR thing was announced when he gave 15 billion dollars to AIDS. He knew what he was talking about."

Politics aside, personal interaction caused John to change his view of Bush.

"One of the old adages in life is never judge someone until you meet them," John said. "I didn't like his policies but I have to say when I met him, I found him charming, I found him well informed and I found him determined to do something about the AIDS situation so I changed my opinion of him. And his wife was astonishingly kind to us well. So it was -- I learned a lesson."

Less surprisingly, Elton John gives President Obama high marks too and says he's doing "a great job."

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"I have never met President Obama, but he revoked the law that you couldn't get into America if you were HIV positive," John said. "Don't Ask, Don't Tell- out the window. Gay marriage, in favor of- endorsed it. He's breaking down the barriers so much and people like Jay-Z came out and endorsed gay marriage and decriminalization. He's a huge hero in the African-American culture."

Sir Elton John has made fighting AIDS -- the disease, the stigmatization of it, finding a cure for it -- one of his most passionate endeavors. But it wasn't always a driving force in his life, which he readily admits in a new book: Love Is the Cure. Everything changed in the late 1980s, when he met Ryan White, the teenage boy who became a symbol of the struggle against AIDS when he was expelled from his middle school after contracting AIDS from a blood transfusion.

"He was a friend, he was an inspiration," said John, "It's because of him, his mother Jeanie who's here today, and Andrea his sister, that I changed. They changed the way I thought about my life, and it was their influence on me that got me to change the way I lived, to look at my life and look at how awful I was, how selfish I was."

The singer and activist was in Washington, D.C. Monday for the AIDS conference, and to view for the first time ever the AIDS Memorial Quilt project.

ABC News' Sarah Burke contributed to this report.