Britney Spears is reportedly planning to marry paparazzo boyfriend ADNAN GHALIB - in a desperate bid to win back custody of her children. The concerned family of the already twice-wed singer have approached lawyers about the "very likely" possibility of a wedding - because the 26-year-old's recent erratic behaviour, including a sudden trip to Mexico on Wednesday (08Jan08), has raised fears over whether the star will elope. A source says, "Lawyers are now on red alert in case she does get married. Britney is very unpredictable at the moment. But the feeling is that a wedding is very likely. "Her family have discussed with lawyers what could be done if she does suddenly fly away and tie the know. They are preparing to argue that she is not in a sound state of mind - that she is strung out on so many prescription drugs that she does not know what she is doing. "The trip to Mexico had everybody running scared that she had disappeared to get hitched. For a few hours nobody knew where she was. She had disappeared. And that never ever happens." Spears further fuelled reports of marriage to the British snapper on Friday (11Jan08) when she browsed cars at a Mercedes-Benz dealership with Ghalib wearing a lacy white wedding gown - the same dress she wore to her reception when she wed her second husband Kevin Federline in September 2004. Their divorce was finalised in July 2007. Spears had visitation rights to sons Sean Preston, two, and Jayden James, one, withdrawn after sparking a three-hour stand off with emergency services when she refused to hand them over to Federline following a supervised visit last week (03Jan08). She must attend a court hearing in Los Angeles on Monday (14Jan08) in order to determine whether she is eligible to win back custody of her kids.