TMZ has learned Sean Preston and Jayden James were returned to K-Fed tonight just before 11:00 PM PT.
We're told that while cops were at the troubled pop star's home, they discovered Spears "under the influence of an unknown substance."
Several ambulances have been called to the scene.
Brit's Kids Are Safe, She's Under the Influence!
1/4/2008 4:26 AM PST BY TMZ STAFF
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