Rebekah Vardy has confirmed she tried to leak a story about footballer Danny Drinkwater being arrested for drink-driving to the Sun, during a tough day in the witness box.
But she told the High Court the attempt to leak the story was a one-off.
Mrs Vardy was giving evidence on the second day of her libel case against Coleen Rooney.
Mrs Rooney is being sued for libel after claiming Mrs Vardy leaked private information she obtained on Instagram.
In court on Wednesday, Mrs Rooney's barrister David Sherborne read a WhatsApp exchange between Mrs Vardy and her agent Caroline Watt.
The High Court heard that Mrs Vardy had told Ms Watt that she wanted to be paid for providing information about Drinkwater leaving police custody after crashing his car.
Mr Drinkwater is a former Leicester City team-mate of Mrs Vardy's husband, Jamie.
Mr Sherborne said Mrs Vardy sent information about Mr Drinkwater spending a night in prison to Ms Watt, along with the message: "I want paying for this x."
After she was told the Sun had already obtained the story about Mr Drinkwater's arrest from another source at the police station, Mrs Vardy said she was "fuming I didn't give it to you [Ms Watt] earlier".
Ms Watt replied: "That would have been a fortune," along with the cry-laughing emoji, and instead suggested getting in touch with paparazzi agency Splash News to provide further information about Mr Drinkwater.
Mrs Vardy confirmed the exchange of texts referred to the possibility of the Sun writing a story but, with regard to wanting payment, said that "wasn't a serious comment".
"It was a fleeting thought and one I didn't consider any more then when I wrote it," she said.
Mr Sherborne suggested Mrs Vardy was angry about "the fact that you're not going to get your money". She replied: "No, that's not true."
When asked if Andy Halls, a reporter for the Sun, was a "good conduit" for information, she said: "No, that's not the case. I never gave him information."
Mrs Vardy later denied having built a special relationship with the tabloid and stood by remarks in her witness statement that she "actively avoided" forming relationships with journalists, after being shown Instagram messages which revealed she planned to meet with another Sun reporter for lunch.
Quizzed on whether she stood by an earlier witness statement in which she said she had never been paid for private information about anybody apart from myself or my family, she replied: "Yes, apart from the Danny Drinkwater one."
Mr Sherborne said: "So, there's an exception... I put it to you that when you say in that witness statement that these conversations were never serious and Caroline [Watt] would have understood that, that's completely untrue isn't it?"
"No, it's not," Mrs Vardy replied.
Mr Sherborne continued: "What this shows, Mrs Vardy, is that you are prepared to lie under oath." She replied: "No."
Earlier, Mrs Vardy denied it was "standard practice" for her to pass private information to the Sun via her agent.
Also on Wednesday, Mrs Vardy conceded that she had directed her agent to look at Mrs Rooney's private Instagram account to obtain information about a car crash.
In one exchange from January 2019, the court heard that Ms Watt asked Mrs Vardy: "Am I imagining this or did you say yesterday that Coleen had crashed her Honda?"
"She defo [definitely] has... Go in the Instagram," Mrs Vardy replied, according to court documents, referring to Mrs Rooney's private Instagram account, which Mrs Vardy could access from her own account because the pair followed each other.
Mr Sherborne noted that, on the first day of the trial, Mrs Vardy had agreed it would have been "wrong" if Ms Watt was looking at people's private Instagram posts through the use of Mrs Vardy's own account.
He put it to Mrs Vardy on day two of the trial that, in this instance, she was directing her agent to Mrs Rooney's Instagram. "Yes, I am," Mrs Vardy replied.
The car crash story appeared in the Sun newspaper but Mrs Vardy denied having been the source.
Mrs Vardy said it was "undeniable" that her agent had seen something on Mrs Rooney's Instagram account, but said she had no knowledge of Ms Watt "monitoring" it.
"If she had been monitoring Mrs Rooney's Instagram, I had no knowledge of her monitoring it and I didn't ask her for that," she told the court.
Mrs Vardy added that she had been "just joking" when discussing leaking another story with Ms Watt, this time about a woman allegedly cheating on her husband with a famous footballer.
She said WhatsApp messages between herself and Ms Watt were often "outrageous and inappropriate", but said it was just "gossip between friends" and not evidence of leaking stories.
The so-called "Wagatha Christie" trial centres on a viral social media post in October 2019, in which Mrs Rooney said she had carried out a "sting operation" and accused Mrs Vardy of leaking "false stories" about her private life to the press.
Mrs Rooney, the wife of former England footballer Wayne, claimed the only account that could have seen three fake stories she had posted on her personal Instagram account - which later appeared in the Sun - was Mrs Vardy's.
Mrs Vardy has denied being the source of the leaks and said a number of people had access to her accounts. Ms Watt has also denied being the source and has been deemed too ill to testify.
The libel case, which will be settled by a judge, not a jury, is set to run until next Wednesday and the onus is on the defendant Mrs Rooney to prove that it was in fact Mrs Vardy who leaked the stories in question.
The claimant, Mrs Vardy, started to cry in the witness box towards the end of proceedings on Wednesday, when reminded about abuse she and her family had received at the hands of online trolls as a result of the allegation.