In yet another perplexing move, Britney Spears canceled a duet she was to record with her ex, Justin Timberlake and superstar producer, Timbaland, reports the New York Post. A music industry insider tells the paper that Justin wrote the song specifically for Britney. "Timbaland set aside a week out of his crazy schedule to do this — and then, just before she was supposed to fly out, Britney abruptly canceled the sessions and refused to do the song." Britney who's been working on her new album in between her custody battle with Kevin Federline, was also rumored to be opening next month's MTV Video Music Awards. "It's crazy," adds the insider. "She's looking for a comeback, and this would have not only been a huge hit, but something she could have opened the [show] with and really blown everyone away." Another Post insider believes Britney needs professional help. "People like her are sick. She needs help. It's sad because what she's got — and we've heard it's like bipolar disorder — can easily be treated with medication, but she won't do it."