Britney Spears refuses to sing with Justin Timberlake.

Britney has made several questionable choices in her life. This one is a doozy. Even I can see that an opportunity like this was gold. To pass it up is bananas...
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Britney Spears backed out at the last minute from recording a duet with her old flame, Justin Timberlake - and the inexplicable decision last month has suits at her record label, Jive, very worried.
The duet, which was to be produced by hit-maker Timbaland at his studio in Virginia Beach, could have started a big comeback for the troubled pop tart, who peaked before she had two marriages and two kids.
A music industry source said Timberlake wrote the duet specifically for Spears. Although they wouldn't be together in the studio, his voice would have been mixed with hers later.
"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 session and refused to do the song.
"It's crazy," the insider added. "She's looking for a comeback, and this would have not only been a huge hit, but something she could have opened the MTV Video Awards with and really blown everyone away."