Madonna has become so nuts for coconut water that she recently invested about $1.5 million in one of the leading makers of the drink, which has taken Hollywood and The Big Apple by storm, The Post has learned. Guy Oseary, the Material Girl's manager, told On the Money in an exclusive interview last week that the superstar decided to invest after she learned about the product from a September story in The Post. Oseary is also investing seven figures in the company, New York-based Vita Coco, and has rounded up pals like actors Mathew McConaughey and Demi Moore, and the Red Hot Chili Peppers' Anthony Kiedis, who are making smaller, but "significant investments." The total investments, estimated to be under $10 million, will amount to a minority stake in Vita Coco, which has been valued at between $120 and $140 million by industry analysts. Madonna, who Oseary said started drinking coconut water on her world tour last year, doesn't look like she is going to be a passive investor -- she's already lobbing some business ideas at company founder Michael Kirban. For example, she thinks it would be a marketing winner if the company made coconut-water popsicles. Madonna is so enthusiastic about coconut water -- the clear juice from young, green coconuts, not the brown coconuts that have a milky liquid center -- that she drank fresh coconut juice daily on the overseas leg of the Sticky & Sweet tour. There is also talk that she might make a follow-up investment. Oseary said he and Madonna were attracted to the financial side of the business because it is vertically integrated -- they own their own factories -- and because they are independent. "The fact that they are saying no to everyone who wants them is pretty cool," he said."You want to go to the party that no one else is invited to." As reported in these pages, Vita Coco, which expected to log $40 million in sales this year, turned down multimillion-dollar investments from beverage industry giants Coke and Pepsi -- opting to try to make it alone in the highly competitive water wars. Vita Coco has 60 percent of the market, but competes with two other brands, Zico and ONE. Kirban, 34, who started the company with pal Ira Liran in 2004, hopes to use the investor cash to expand distribution beyond New York and LA.

"American Idol" star Adam Lambert has a mentor in Madonna, after she gave him career advice during a guitar lesson at her New York City home. Adam was stunned when he discovered his guitarist was Madonna's guitar teacher, and thrilled when he was invited to her house for a music lesson. Lambert told Oprah, "That was actually the first time I can remember getting super star struck ... I had a great conversation with her. My guitar player is her guitar teacher and, we were both in New York, and he said, 'You know, I'm giving her a guitar lesson. Would you like to come over?' "I went to her house ... and she came in in, like, no make-up, yoga wear, just totally Zen. ... She walked into the room and her presence is very powerful ... and, at first, I could tell she was kinda checking me out ... and the first thing I said to her was, 'Oh my God.' "I talked to her about celebrity and how to deal with it all and she gave me a couple of words of wisdom -- she said, 'Just keep your eye on the prize and put your blinders up and don't get sidetracked with all the extra fuss.'"
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Madonna Public Relations spokeswoman Liz Rosenberg is denying gossip reports that the singer is rekindling her romance with loser Sean Penn, after the former couple were spotted together in New York City. Madonna was rumored to have revived her relationship with Penn, who she married in 1985, after they were seen chatting over a meal at Adour restaurant in the city on Thursday. But the Material Girls publicist is insisting it was a chance meeting between former lovers - and not a date at all. Rosenberg says, "Madonna was at the St. Regis having dinner with friends. Sean stopped by the table to say hello. He sat for ten minutes and then left. Madonna continued with her dinner. That's all it was."
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Pop icon Madonna will once again be reunited with ex-hubby Guy Ritchie. The former husband and wife will celebrate Christmas with their children. It now appears a very nice family reunion will take place in Britain with the children, so they can spend Christmas Day with the director at his country estate in Wiltshire, England. A source tells a British newspaper, "Madonna is flying in for 24 hours so Guy can spend Christmas Day with the children. Things are amicable between them and the children love Christmas at Ashcombe House in Wiltshire, which Guy has turned into a Santa's grotto." They divorced in January, 2009.
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