The Who rocker Roger Daltrey is struggling to find American icons to join him for his latest cancer charity benefit - because they all expect to be paid to perform.

The Won't Get Fooled Again singer attracts the cream of British music to his annual charity shows in London, but he's having a problem persuading big names to play his upcoming concert in Philadelphia, Pennsylvania.

In a webchat on Tuesday (01Jul14), Daltrey wrote, "I could do with more support from some of that side of the business. And I don't mind saying so, because your country baffles me. In Britain, any kind of charity work is unconditional. In America they kind of expect to get paid for it, I find that extraordinary.

"One of the things we're struggling with is getting more Americans involved, more American entertainers like myself, the backbone of the music industry was this age group, and I feel like if you've been successful and you've made it, just by donating a bit of your time, a bit of your energy, even if it's just talking about what we are trying to achieve now..."

But he has secured Joan Jett and can't wait to perform with her: "I've known Joan Jett obviously for years. She's a real rocker and she still cuts it, really cuts it."

The 28 July (14) gig is a fundraiser to build a cancer space at the Children's Hospital of Philadelphia.