Brit's Assistant Gets Served

Britney Spears' parenting skills just got served...as did her most trusted hanger-on.

Alli Sims, Spears' honorary cousin, off-on personal assistant and wannabe pop star, was subpoenaed at a Hollywood house party early Sunday in connection with Spears and Kevin Federline's ongoing custody battle, a source confirmed to E! News.

Sims, who recently returned to the post of Spears' right-hand woman after being briefly displaced earlier this year, was served with the legal papers just after 2:30 a.m. Sunday while leaving a party in the Hollywood Hills. While Spears was also in attendance at the party, the star did not witness the serving.

The deposition subpoena, issued at the behest of Federline's attorney, Mark Vincent Kaplan, requires Sims to testify about Spears' parenting skills in the ex-couple's custody case and was served guerrilla style by IMS Security's Aaron Cohen.

Sims was leaving the bash with music producer J.R. Rotem, who's overseeing Spears' comeback project, and despite evasive action by Sims and Rotem, Cohen managed to serve the subpoena by forcing the document through an open car window.

Kaplan is expected to question Sims on everything from what and how frequently Spears feeds sons Sean Preston, 23 months, and Jayden James, 11 months, how late they are allowed to stay up, how much time mom spends caring for the boys and Spears' party habits.

Last Wednesday, Federline filed documents requesting "primary physical custody of his two children" in Los Angeles Superior Court, amid increasing tabloid reports of Spears' erratic behavior and questionable parenting prowess. The next hearing is scheduled for Tuesday.

But the 26-year-old Sims may not be the most impartial witness. While there is some question as to whether they are blood relations, she and Britney grew up together in Louisiana and have been inseparable for much of Spears' tenure in Hollywood.

Even after Sims left Spears' employ earlier this year, she had nothing but glowing things to say about Britney. Sims told People earlier this month that Spears is "a wonderful mom, and she is so hands-on...Britney loves those babies to death. And they adore her."

Clearly, Spears had a slightly better rapport with Sims than her replacement. Just three weeks after hiring her as a personal assistant, Spears gave Shannon Funk her walking papers last month, in the wake of a disastrous, image-damaging OK! magazine cover story in which Funk was alleged to have purloined several designer goods from the shoot. A source told E! Online at the time that Spears thought Funk was "rude," "unprofessional" and trying to control her.

Shortly afterward, Spears reportedly rehired Sims.

Meanwhile, while Spears and Federline's custody battle is heating up, their marriage has finally wound down. On July 30, a judge signed off on the couple's divorce, with the duo agreeing, at least for the time being, to split custody of the boys and for Spears to pay Federline $15,000 a month in child support.