Feeds
Rex Features
The singer was hospitalised after refusing to give her two children back to their father, Kevin Federline, who won primary custody following the pair's divorce.
Now more details of the incident on Thursday night have apparently emerged.
The News Of The World says the heavy police presence outside Spears's Hollywood mansion was because Federline realised she had two guns, including a Beretta pistol he gave her for a birthday.
A source said: "K-Fed was terrified. He realised she had a gun where she was holding them."
It is also claimed Federline realised there was a problem when Spears phoned him offering money to keep the children.
"Britney said that Kevin could have an incredible $100 million if he'd give her the kids and never see them again," said a source. "He's used to Britney going off on one, but he knew from her voice that this was a whole other thing entirely.
"He hung up straight away and called his legal team in a panic. He told them that Britney was capable of anything and admitted that she still kept two handguns at the house - the pistol he bought her for a birthday gift and a black automatic Glock. The lawyers called the police immediately."
After the stand-off, police said Spears was under the influence of an "unknown substance". The paper reports it was not illegal drugs but a mixture of prescription medicine.
She has now been released from hospital.
