Britney Spears has reportedly been showing signs of her old, unstable ways behind-the-scenes of 'The X-Factor.'

A source told New York Daily News, "She acts like she has a different contract than everyone else. She shows up late, she wanders around aimlessly, and she is in her own world. She wasn't ready for this responsibility."

Spears, who was paid $15 million for her first season - and possibly only - season of the reality show, has reportedly disppaointed Cowell, who expected her to bring in the ratings in the second season.