Britney Spears' testimony, or lack thereof, will be key in Sam Lufti's defamation trial against her mom, experts say

Britney Spears’ personal and professional life are on the upswing with her coveted position as a judge on “The X-Factor” and marriage proposal from agent Jason Trawick. But the pop star’s public meltdown five years ago is set to be dredged up in a Los Angeles courtroom this week, as the lawsuit filed by her former manager and confidante Sam Lutfi finally goes to trial.

Lutfi filed suit in February 2009 for libel, defamation, battery, intentional infliction of emotional distress and breach of contract following the publication of Britney’s mother Lynn Spears’ book “Through the Storm: A Real Story of Fame and Fortune in a Tabloid World.” Lutfi alleges that the book is riddled with libelous statements about him (including allegations he drugged Spears) which in turn caused him to suffer “humiliation, mental anguish and emotional and physical distress.” In addition, Lutfi is suing for a portion of the profits made off Spears’ 2007 album “Blackout,” and related earnings over the period he insists he was her manager.

Yet Spears, who has been under the co-conservatorship of her father and attorney Andrew M. Wallett since 2008, is not expected to be anywhere near the courthouse, at this stage anyway, The probate judge overseeing the conservatorship, which now also involves her fiancé, has ruled that the pop princess should not testify as it could potentially cause her “irreparable harm and immediate danger.” Yet Lutfi’s legal counsel have argued that Spears should take the stand as they anticipate that her testimony would adhere to his claim he only sought to protect her.

With or without Britney, legal experts predict the trial – expected to last three weeks – could get mighty nasty.

“It will be explosive for so many reasons. Britney’s epic meltdown, in which the world witnessed her shaving her head and attacking the paparazzi with an umbrella, is once again going to be revisited. If Britney is indeed called, things could get very ugly fast,” California-based civil litigation attorney Anahita Sedaghatfar told FOX411’s Pop Tarts column. “Some of the allegations made by Lutfi are that Britney was using drugs and that (she told him her dad) was violent and racist. Questioning Britney about these issues would be fair game if she takes the stand, and this would not be good for her any way you look at it."

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Leading defamation attorney Mitchell Langberg concurred that Spears’ presence on the stand would make proceedings “interesting,” to say the least.

“If her mother was not telling the truth and Britney has to testify, she will be in an uncomfortable situation. Perhaps the biggest question mark here is what will Britney say? Both sides can’t be right and juries have an uncanny ability to sniff out who is telling the truth,” he said. “For Britney, there is probably not a whole lot at stake unless she is forced to testify. For Lutfi, his reputation is really what is at stake. He is either going to come out of this with the jury determining that what Britney’s mom said was true, which could ruin him in this town. Or the jury is going to conclude that Britney’s mother was not telling the truth, in which case Lutfi will likely come off as the hero who was protecting Britney from her folks.”

The outcome at this early stage is shaping up to be a “hard call," Langberg said.

“Lutfi has the burden of proving that the statements about him were false and that Britney’s mom knew they were false or had serious doubt to their truth when she published them. From all reports, he intends to bring in the witnesses, including Britney's cousin, who will deny the allegations that Britney's mother made.  If that is what happens, she may have a hard few days in court,” Langberg remarked. “On the other hand, if just one reliable source confirms that she told Britney's mother these things, that should be enough for her to successfully defend the defamation claims.”

According to Sedaghatfar, the case could continue to be stretched out far beyond the estimated trial period.

“The issue of Britney testifying will be the most significant aspect of this trial, will be contentiously litigated and will likely be the subject matter for appeal,” she added. “This case is not going away anytime soon.”

Reps for Spears and Lutfi did not respond to a request for comment.