Cousin to testify about Britney's parenting

Britney Spears' cousin Alli Sims will testify during the forthcoming custody battle between the star and her ex-husband Kevin Federline.

Sims - who has worked as a personal assistant for the Toxic singer - was served with a deposition subpoena, demanding that she testifies about Spears' parenting skills, when she left a Hollywood party at 2.30am on Sunday morning.

"Alli was really shocked and covered her face," a witness is quoted by The Sun as saying. "She was really distraught and said: 'Oh my God.'"

Federline's lawyer Mark Vincent Kaplan has confirmed that the rapper wants Sims to give a deposition because she has "relevant information" to reveal to the court.

Kevin is hoping to gain sole custody of their two children Sean Preston and Jayden James, and is expected to claim that troubled Britney is an unfit mother.