The star's comeback performance was swiftly panned by critics as Britney appeared to lip-synch out of time and her dance routine seemed sloppy.

It was widely speculated that the pop singer was nervous about her performance but now it is claimed that she also flipped about her hairstyle and lashed out at her stylist before the show, the Sun reports.

A source told the tabloid: "Britney took enough to floor an elephant. They calmed her down, but were clearly too effective. The scene in the dressing room before the show was one of absolute blind panic.

"She knew she hadn't rehearsed enough and was going to mess up the whole show and possibly her career - then she saw her hairdo and it was the final straw."