Ne-Yo admits it: He was holding Hayden Panettiere's hand Monday night as the two hit a New York City nigtclub, but the two are not dating. He swears. "Hayden and I just met yesterday. We've only known each other for one day," Ne-Yo told PEOPLE at the Ronald McDonald House Charity's World Children's Day event Tuesday, where Panettiere, 18, also made an appearance. "She was hanging out with some friends and invited me to come out." As for the hand holding, "I was helping her out of the car!" says the singer, 28. "She had these shoes – they were cute – but they were torture devices, so I had to help her." The duo only spent 48-hours together as they toured Ronald McDonald Houses in Dallas, Detroit, Philadelphia, and New York, but they definitely hit it off. "I'm a fan of Hayden's show Heroes, so I was excited to know she was going to do this with me," the singer continued. "Hayden is cool people. She's a little silly. But silly is good." Having gotten along so well, there may be a business collaboration in their future. "We talked about me possibly writing a song or two," for Panettiere's long-delayed album, says Ne-Yo, who is also working on the upcoming Michael Jackson album. "I'd do it if she needed me to."