While her whereabouts is unknown, it is rumored she had gone to rehab for an "eating disorder and addiction issues."
Demi - who split from husband Ashton Kutcher in November amid speculation he had cheated on her - and Deepak are old friends, with her visiting him in India in 1996 and she even served on the board of advisers at his Californian healing center, according to People magazine.
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Speaking about Deepak's book 'The Seven Spiritual Laws of Success' she has previously said: "It is a practical guide to the fulfillment of your dreams. Deepak is also teaching me how to live healthily and longer."
Deepak - who has published over 65 published works in a career spanning more than thirty years - has been involved with many celebrities, but says this gives an unfairly skewed view of his work.
He said: "Celebrities call me after they read my books and come to my seminars [although] less than one per cent of the attention is from Hollywood. Ninety-nine percent is from the general populace."