Kevin Federline is introducing a secret witness to help his court battle to seize custody of his two children with pop star Britney Spears. Lawyer Gloria Allred - representing Spears' ex-husband - will accompany the male witness to a closed hearing in Los Angeles, in a bid to remove Sean Preston, two and Jayden James, eleven months, from Spears' care. According to Foxnews.com, the witness has submitted a written testimony, claiming that the children witnessed Spears using drugs in their home. The witness will appear in court - but won't need to testify unless his testimony is questioned by Spears' legal team. Allred has reportedly told Fox that the witness is "not famous" and is "just someone who is concerned about the kids". Spears and Federline's two-and-a-half year long marriage ended in March 2007.