The singer and her ex-husband were expected in court later in the day.
Superior Court Commissioner Scott Gordon, who has said there is evidence Spears is a "habitual, frequent and continuous" user of drugs and alcohol, withdrew approval for her to even visit the children after finding she had failed to comply with some conditions for shared custody.
He later withdrew the ban and allowed her to visit Preston, 2, and Jayden James, 1 - but only in the presence of a court-approved monitor.
The order by Gordon was tough and unambiguous.
Spears was to undergo random drug and alcohol tests and meet weekly with a parenting coach who would report back to the court about her parenting skills. Spears and Federline also were prohibited from making derogatory remarks about each other in their children's presence and from using "corporal punishment" to discipline them.
Both parents also were ordered to complete the court's "Parenting Without Conflict" class.
The custody fight has played out on a public stage, with paparazzi and celebrity Web sites reporting on the former couple's every move — including sightings of Spears driving with her sons and a monitor in Beverly Hills.
On Thursday, another Spears lawyer entered a not guilty plea for her on a misdemeanor charge of driving without a valid driver's license.
Michael Flanagan said Spears recently obtained a California license and he hoped the charge would be dismissed.
At the same hearing, a Superior Court judge dismissed a hit-and-run charge stemming from an Aug. 6 accident. Flanagan said his client had paid an undisclosed amount to the woman whose car the star hit in a Studio City parking lot.
