It's probably the long hiatus that she's taken and her much-publicized meltdown that has fuelled rumors of pop star Britney Spears being a nervous wreack before her 2009 world comeback tour.

Mum Lynne revealed that the singer, who put up with two tumultuous years during which she lost the custody of her two sons followed by her trips to rehab, needs a push to up her confidence.

"That gut belief she had in herself is what's missing," the Daily Star quoted Lynne as telling a US magazine.

"The hardships she has been through have made her a little hesitant. She needs one big boost and she'll be there," she added.

The pop princess, who took to the stage on the live X Factor semi-final in November - her first UK performance in five years - had been unable to impress the critics, who described her performance as shaky and less than dynamic.

Britney also appeared to be nerve-wrecked at a free concert at the Big Apple Circus Tent in New York at the launch of her latest album 'Circus'.

A network source revealed that the 'Womanizer' hitmaker had admitted to being a "bundle of nerves" before going on ABC's Good Morning America.

Source-ANI
TAN/M