London (CNN) -- The former husband of celebrity chef Nigella Lawson will take the stand Thursday in the trial of the couple's former personal assistants, who are accused of defrauding them of 300,000 pounds (U.S. $488,000).
The British court heard earlier this week at a pre-trial hearing for the assistants that Lawson and ex-husband Charles Saatchi had a "culture of secrecy" around their marriage.
In the hearing, the defense read an e-mail from Saatchi to Lawson about the allegedly embezzled money, saying that the assistants would "get off" because, he wrote, Lawson was using cocaine and marijuana on a daily basis and "allowed the sisters to spend whatever they liked."
Representatives for Lawson declined to comment on the allegations, citing the ongoing court proceedings.
The defense also read a statement from Saatchi saying that he learned of Lawson's alleged drug use in June, around the time the couple were photographed in a restaurant having an argument.
In the photos -- which were splashed across the front pages of national newspapers at the time -- Saatchi is seen with his hand around Lawson's throat. Saatchi, a renowned art collector, accepted a police warning for assault, and the couple announced they would divorce soon after.
The defense claimed that the e-mails showed both Saatchi and Lawson had attempted a "manipulation of the court" and that the case should be thrown out. The judge ruled the trial would proceed.
The former assistants, Italian sisters, have denied they embezzled any money from the couple.