Country music superstar Toby Keith had to reject 20 stars' offers to take part in his summer (13) tornado relief concert in his native Oklahoma, after becoming inundated with requests from so many big-name volunteers eager to do their part for charity.

The singer/songwriter's celebrity-studded July benefit, which featured Garth Brooks, Trisha Yearwood, Willie Nelson, Ronnie Dunn and Sammy Hagar, helped raise $2 million (£1.3 million) for Oklahoma tornado victims.

And the big gig at Memorial Stadium on the campus of the University of Oklahoma was such a hit, he's convinced he could have sold it out if he staged it in Africa.

But he felt awful having to turn celebrities keen to take part away.

He tells Wenn, "So many big stars came in for that, that I had to cut people off. The last 20 people who called and said they wanted to show up for it, we had to say, 'We're done'."