ABC News’ Sarah Burke reports:

Natalie Cole – legendary singer and daughter of iconic jazz performer Nat King Cole – told ABC’s Rick Klein on “ Top Line” today that she has sung for five presidents, including Reagan, Carter, Bush, Clinton and Obama.

Recalling a performance at George W. Bush’s White House, Cole described how the president would tap his toes and snap his fingers to the music. “I think that his wife didn’t want him to look like he was enjoying himself too much,” she remembered. “I loved it. I thought it was great.”

Most recently, the singer paid a visit to the White House in February 2010, where she performed Marvin Gaye’s iconic “What’s Going On?” Cole was one star in a constellation of distinguished musicians – including Bob Dylan, Smokey Robinson and John Legend – who were invited by President Obama to honor and celebrate the music of the civil rights era.

Of her experience performing at  White House events, says Cole, presidents like to maintain their formal composure in front of their guests. Even though they can be somewhat reserved, said Cole,  “if you work on them enough, they loosen up eventually.”

Cole stopped by ABC’s “Top Line” today to talk about her ongoing campaign against the stigmatization of hepatitis C.  The singer learned she had the disease in February 2008, having contracted it through intravenous drug use years earlier.  Since 2008, Cole has been a public advocate for the cause. Through the “ Tune in to Hep C” campaign, she hopes to eradicate negative preconceptions of the disease, improve diagnosis techniques and broaden access to treatment.  

“There’s so many ways now that we can get to this disease,” she said, ”and confront it without it having that perception of evil that it used to have so many years ago.”