Britney had tracked down her mom with the help of the paparazzi who are never far from her side.
The singer's bodyguards had asked some of the fotogs who camp outside her Beverly Hills home if they knew the whereabouts of Lynne Spears.
When the shutterbugs said the elder Spears was holed up nearly an hour away at a TV studio in Valencia, the singer grabbed her two kids — Sean Preston, 21 months, and Jayden James, 9 months — and hit the road in her Mercedes.
With security men in a pair of SUVs flanking her, Spears arrived at set of the kiddie show "Zoey 101," on which little sister Jamie Lynn Spears co-stars.
Britney, 25, stormed out of her car and right to a trailer where she found her mom.
Spears — wearing a tank top and denim shorts — then handed Lynne, 52, a picture frame and set of papers, including a lawyer's letter warning her to stay away from her grandkids if she's on any medication that might cause her to be impaired, according to celebrity Web site TMZ.