Kings of Leon guitarist Matthew Followill is set to become a first-time father -- his wife is six months pregnant, according to a U.K. report.

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The rocker and his songwriter partner, Johanna Bennett, are expecting their first baby together in late spring, reports Britain's The Sun.

A source tells the publication, "Although Jo and Matt haven't made any announcement it's well known among her friends that they're having a child.

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"They are both absolutely thrilled and can't wait to become a proper family. They don't know what they're having but don't mind either way.

"The rest of the band are just as chuffed and are looking forward to meeting the new arrival as he or she will be the first Kings of Leon baby."

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The couple wed in 2009.