Lady Gaga says she has 'begun to cherish my loneliness': Who is the saddest celebrity?

Lady Gaga is unbelievably rich and arguably the biggest pop star of her generation. But believe it or not, the 26-year-old is still quite sad. On Lifetime's "The Conversation With Amanda de Cadenet" on Thursday, the singer admitted that she has "begun to cherish my loneliness. I have, sort of, since I was around 20 years old."

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In the interview, Gaga reveals that she was very depressed when she was 19. "I would go back to my apartment every day and I would just sit there. It was quiet and it was lonely. It was still. It was just my piano and myself. I had at television and I would leave it on all the time just to feel like somebody was hanging out with me."

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She also confesses that she used cocaine to "fill that void," like "the drug was my friend." While she's now drug-free, Gaga is reportedly taking a "break" from her hunky "Vampire Diaries" boyfriend Taylor Kinney, leading us to wonder if she's lonely all over again. From Gaga to Demi Lovato to Sinead O'Connor, let us know: Who is the saddest celebrity?