Britney Spears shaved her head last week

Federline was due to appear at an emergency hearing in a family law court on Thursday before it was called off.

Spears' manager Larry Rudolph confirmed she was in a rehabilitation centre for reportedly the third time in a week.

It was not known what the court hearing was about but the former couple are in dispute over custody of their children.

"Kevin continues to be a very focused father with his children with hands-on management," his lawyer Mark Vincent Kaplan said.

Kevin Federline was married to Britney Spears for two years

Los Angeles Superior Court spokesman Allan Parachini said Mr Kaplan had cancelled the court appearance. The court did not give an explanation for the cancellation.

Mr Rudolph said Spears had entered the Promises Malibu treatment centre on Wednesday evening.

Spears, 25, has two children with Federline - five-month-old Jayden James and Sean Preston, aged 17 months.

The couple currently have joint custody under a temporary court order.

Spears reportedly sought treatment at a rehabilitation centre in the Caribbean last week but left after just one day.

US media then reported she had gone into the Promises rehabilitation centre in Malibu earlier this week but again left a few hours later.