Kevin Federline, Britney Spears' former husband, has subpoenaed a friend of the pop star as he tries to gain primary custody of the couple's children.

Spears' friend Alli Simms was approached by private security as she left a party in Hollywood Hills and served with legal papers.

The documents are a deposition subpoena on behalf of Federline's lawyers that asks Sims to testify about the Baby One More Time star's parenting skills.

Us magazine reports that the rapper, who met Britney Spears while working with her as a back-up dancer, has concerns about the welfare of the two children from their marriage.

On August 8th he filed for primary custody of 23-month-old Sean Preston and 11-month-old Jayden James in an LA superior court.

His attorney told the publication: "Kevin would like to have as much custody as he could because he feels that the children would benefit from that."

Spears left the party later and did not witness the serving of the papers.

She recently finalised her divorce from her husband of three years and since their split has engaged in bizarre behaviour such as attacking photographers with an umbrella and even shaving her head.

In the past, Spears has been photographed driving a car with her baby on her lap.

13/08/2007 07:38:22