Jewish mysticism has transformed Madonna, Karen Berg, the co-founder of the worldwide Kabbalah Center, told The Jerusalem Post Thursday in an exclusive interview. "If you compare her 13 years ago, when she started studying, and today, she's a changed person," said Berg. "She's a good human being, she studies, she wants depth. She's a ravenous student. She's a very highly intelligent and spiritual human being. "She reads and follows Hebrew, and has learned how to speak some Hebrew," said the religiously observant Berg, who attended the final show of the singer's Sweet & Sticky tour at Hayarkon Park on Wednesday night. "Last night before she started her show, she was thanking everybody who was there, humbler than I've ever seen her before. She really had appreciation for the people around her," said Berg, who has also written several books based on Kabbalah including God Wears Lipstick: Kabbalah For Women. The Kabbalah Center, based in Los Angeles, but with more than 50 branches worldwide including in Tel Aviv, teaches principles of Kabbalah to a wide audience of secular Jews and non-Jews alike. Berg explained that the singer showed up unannounced at the Kabbalah Center in Los Angeles in the 1990s and began sitting in on classes. One of the center's teachers, Eitan Yardeni, who was also in Israel this week, has guided the pop icon throughout her Kabbalah studies. Other celebrities who have studied at the center, which Berg opened with her husband Philip in 1984, include Lindsay Lohan, Ashton Kutcher, Demi Moore and Donna Karan. Madonna has worn a red string around her left wrist for protection and to ward off the "evil eye," introduced Jewish ritual objects such as tefillin into her videos and adopted the Hebrew name Esther. She included visuals of Hebrew texts during her Sweet & Sticky shows and according to Berg, no longer appears on Friday nights. Berg said that Kabbalah has also filtered into Madonna's music and her message. "Look at 'Ray of Light,'" she said, referring to the singer's 1998 album and song. "There's a direct Kabbalah reference to it." She also said that Madonna told her she would like to spend more time in Israel, and was disappointed when plans to buy a home here two years ago didn't come to fruition. "She'd like to do more, she'd like to be here more. Like she said at her concerts, she loves the energy here. She said she loves the country and wants to come back," said Berg. Asked how close she was to the singer and if she had Madonna's personal phone number on her cell phone, Berg just smiled and said, "Sure." A full interview with Berg will appear in The Jerusalem Post next week.