He might have spilled out many juicy details about Madonna in his upcoming book called "Life with My Sister Madonna," but Christopher Ciccone doesn't believe the pop singer had anything to do with the breakup of baseball star Alex Rodriguez's marriage.

While a guest on "Good Morning America" this morning to promote his new unauthorized biography of the queen of pop, Ciccone was asked his opinion on recent reports claiming Madonna was behind the breakup of Alex and Cynthia Rodriguez.

"I think it's highly unlikely," Ciccone told ABC's Deborah Roberts on Monday, although he admitted that Rodriguez was Madonna's "type" and it's hard to tell for sure. "Despite everything else, she's still a Catholic girl."

According to Ciccone, the only thing that bonds the two is their interest in kabbalah, the mystical Jewish sect.

"I think that he was interested in Kabbalah, to be honest, and I don’t think… I know Alex from Miami, we’ve met a number of times. I doubt this is actually an affair. I'm sure she had nothing to do with the breakup of their marriage. It seemed absurd to me, truly, I don't believe it," he explained.

Cynthia Rodriguez filed for divorce from the baseball superstar on the July 7 after six years of marriage and two daughters, on the grounds of "extramarital affairs and other marital misconduct."

Addressing the other rumor saying Madonna’s eight-year marriage to Richie is on the rocks, Ciccone praised his sister for her efforts to keep her marriage going.

"She's not the type of person just to walk away," he said, "I believe that she will do what's best for her family and her kids, and I think that she'll do her best to maintain the marriage and keep it going."

Earlier this month, Madonna's spokeswoman denied rife speculation that the 49-year-old singer and the moviemaker were preparing to divorce.

"[Madonna's marriage] is not on the rocks, and there are no plans for getting divorced," Madonna's publicist, Liz Rosenberg told ABCNEWS.com. Rosenberg also brushed off rumors of The Material Girl and A-Rod being anything more than friends.

"Madonna and Alex have the same manager, Guy Oseary," she said. "They have met. They know each other, and Madonna took her kids to a Yankees game last week. There's really not anything to comment on beyond that."