Kid Rock has enlisted some famous friends to lend their voices to his new album, 'Born Free,' which is expected to be released September 7. Among the special guests are Zac Brown on the song 'Flying High,' and Martina McBride, along with rapper T.I., on a tune titled 'Care.'

Martina and T.I. were not familiar with each other before they entered the studio to record the song, which Kid calls a "monster." But they struck up a friendship, thanks to their mutual friend. "I'm the catalyst for everything," Kid tells The Detroit News.

Also appearing on the new project are Sheryl Crow and Bob Seger on the song, 'Collide.' "I asked [Bob] to be on the track, and he didn't call me back," says Kid Rock. "I started getting really nervous, and then a couple of days later he showed up at the studio, by himself. I said, 'Bob, why didn't you call? I didn't think you were going to do it!' He said, 'I was practicing.'"

'Born Free' is Kid Rock's first studio album since 2007's platinum-selling 'Rock 'N Roll Jesus.'

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