The claims are among many by former Seven Network producer Taylor Auerbach that have led to Lehrmann's defamation case against Network Ten being reopened days before judgment was due to be delivered.
The 28-year-old is suing Ten and journalist Lisa Wilkinson over a February 2021 report on The Project in which Brittany Higgins claimed he raped her in a Parliament House office in 2019.
In three affidavits filed with the Federal Court, Mr Auerbach claimed Lehrmann leaked private and confidential texts from Ms Higgins, sending them to Seven ahead of an exclusive interview on the network's Spotlight program.
On Tuesday evening, the court heard the texts were provided to Seven in breach of the so-called Harman undertaking, which sought to ensure evidence from the abandoned criminal case against him was not used for other purposes.
Bruce Lehrmann has denied leaking confidential information. (Bianca De Marchi/AAP PHOTOS)
Lehrmann previously denied in court providing any material to Seven other than his recorded interview.
Mr Auerbach also said Lehrmann was heavily reimbursed by Seven during the lead-up to his explosive interview with the broadcaster, including through lavish meals, flights, a golf excursion to Tasmania and more than $10,000 spent on a Sydney Thai massage.
For the latter, texts attached to the affidavits show a Seven employee trying to reverse the credit card charges to the massage business, instead trying to pay in cash.
Lehrmann allegedly supplied the confidential texts to Seven during the Tasmanian golf trip in December 2022 and later during a "data dump" at a house the network rented for him in Sydney's eastern suburbs.
In January 2023, Seven reimbursed Lehrmann for more unconventional expenses, Mr Auerbach added.
"I recall that monies paid by (Lehrmann) for illicit drugs and prostitutes that evening at the Meriton and the following evening at a brothel in Surry Hills were reimbursed to (Lehrmann) by Seven," he said in his affidavit.
Mr Auerbach left Seven in August 2023 to work as an investigations producer at Sky News.
He said he was fired from Sky in March, due to media reports about an alleged $1000 payment by Seven to Lehrmann for the Thai massage.
Mr Auerbach has threatened to sue Lehrmann for defamation over comments that he was a "disgruntled" employee.
He has also threatened defamation and contractual lawsuits against Seven over the firm's public statements that he had been disciplined for the misuse of the company credit card.
Saying he was "aggrieved" by these suggestions, he sent a concerns notice to Seven and Lehrmann on March 27.
Seven said in a statement it strongly denied Mr Auerbach's "false and misleading claims".
The network said it would never reveal its sources, noting Lehrmann's prior denials that he leaked the texts.
"Furthermore, Seven did not condone or authorise the alleged payments to Mr Lehrmann referred to in the affidavits," a Seven spokesman said.
"The person involved admitted to the misuse of a Seven corporate card and all unauthorised expenses were immediately reimbursed."
On Tuesday night, Justice Michael Lee accepted Ten's last-minute bid to admit fresh evidence, saying it could change the determination of the case.
Network Ten's lawyers successfully argued to reopen the case. (Steven Saphore/AAP PHOTOS)
The reopening of the case means the parties will return to court on Thursday to hear from Mr Auerbach.
The ex-producer's work to secure an exclusive interview with Lehrmann was revealed in court to have involved a $100,000 in-kind payment.
Justice Lee remained hopeful of delivering his judgment in the coming week but would confirm the timing on Monday, he said.
The last-minute hearing came after Ten filed its bid to reopen the case on Easter Sunday.
Lehrmann has settled separate defamation cases with News.com.au and the Australian Broadcasting Corporation over their coverage of Ms Higgins' allegations, receiving $445,000 in legal costs under the agreements.
The criminal case was derailed due to juror misconduct, with prosecutors dropping the charge over fears for Ms Higgins' health.
Lehrmann has always denied any wrongdoing.
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