Music legend Rod Stewart invites ET’s own Mary Hart into his Beverly Hills home as he and his band rehearse songs from his new album — and the star opens up about his marriage, children and even weighs in on "Jon & Kate Plus 8"! Rod’s new CD Soul Book arrives Monday, Oct. 26, and is a tribute to his favorite soul singers of all time -- but he says his wife Penny Lancaster also provided inspiration. “The most difficult song that I sing on the album is a song called ‘Higher and Higher’ by Jackie Wilson and my wife suggested I do that,” he says. “She’s very good for me. And we're good for each other.”