John Mayer is offering fans the chance to spend a day volunteering with him for a veterans' charity project.

The rocker, who donated proceeds from his last tour to help former servicemen and women, will take time out from work to spend a day in November carrying out volunteer tasks for a special scheme to help veterans.

He is urging fans to join in and be in with a chance of spending the day helping out with him and his friends in aid of NCIRE - The Veterans Health Research Institute.

In a post on his website, Mayer writes, "This November, I'll spend a day working on a volunteer project for U.S. military veterans. It'll be myself, a few friends and some veterans working side by side. It turns out I can invite three more volunteers, and each of them can bring a guest."

"We'll work hard on the project and share a meal afterward, and when we go our separate ways, we'll know we've accomplished something great together."