Kevin Federline's lawyer, Mark Vincent Kaplan, served Alli Sims, Britney Spears’s assistant/cousin, with papers, Life & Style reports!

Britney Spears’s assistant Alli Sims served with papers!

At the time of serving, Alli was at an LA house party, and was "absolutely angry" about what was happening, says an eyewitness. Only a few hours earlier, Britney Spears was having dinner in LA with two male friends..

Life & Style reports that the documents state that Alli will be questioned about everything from A to Z about Brit’s parenting skills – including whether she changes diapers, and whether the mom of two drinks too much.

The papers were served by Aaron Cohen, who owns IMS-Security, an elite Hollywood security firm .