Kevin Costner's Estranged Wife Christine Sets Record Straight on Whether Josh Connor Is Her Boyfriend

Christine Baumgartner and the actor are in the middle of a tumultuous battle over child support.

Kevin Costner's estranged wife has denied that a mutual friend is her boyfriend, a notion she refuted on the stand Thursday after the actor made the claim in his most recent court filing.

Christine Baumgartner appeared in a Santa Barbara County courtroom Thursday and testified that the former couple's mutual friend, Josh Connor, is not her boyfriend. Though Costner never mentioned Connor by name in legal documents he filed Wednesday, the actor insinuated as much when he claimed that "her boyfriend recently gave her $20,000."

While emotional at times on the stand at a hearing to determine what Costner should pay in child support for their three children, Baumgartner was asked about her and Connor's July vacation in Hawaii. She was also asked if Connor was her boyfriend and she answered affirmatively, "No."  

Baumgartner, however, did concede -- while wiping away tears -- that Connor gave her $20,000. Baumgartner also testified that she gave half to her mother. When asked why she was being emotional, Baumgartner shared she was concerned about her mother's wellbeing. She also stated that, during the marriage, Costner gave her mother $5,000 monthly, which she said her mother is no longer receiving.

As far as new housing for her and the kids -- after she was ordered to move out of Costner's beach club estate last month -- Baumgartner said she was only able to do so after her brother forked over the $80,000 deposit she needed for a rental property in nearby Montecito. Baumgartner also said she paid him back and she's since signed a 6-month lease for $40,000.

During her testimony, Costner noticeably pressed the bridge of his nose. Earlier in the hearing, an eyewitness told ET that the Yellowstone star seemed "irritated when Christine's attorney said that he should pay for both attorney fees." The eyewitness said Costner shook his head.

Under cross-examination, Baumgartner revealed that the $20,000 Connor gave her was in cash. As for why he gave her the money, she testified that she had no access to money. She also clarified that it wasn't a gift and she planned on paying him back. Costner's attorney also questioned her as to why she went to Hawaii in July after she was awarded $129,000 in child support if she was so concerned about her finances. Baumgartner responded she was more concerned about her mother's anxiety. She also testified Connor paid for the trip to Hawaii.

Baumgartner also explained why she needed her brother to put up the deposit money on the Montecito property, testifying that Costner was supposed to deposit money in her account, but she "panicked" when he didn't. When asked how she'll generate income moving forward, Baumgartner said she might look into teaching or working with kids.

This is the first of two child support hearings between the former couple, who share sons Cayden, 16, and Hayes, 14, and daughter Grace, 13. The court has temporarily ordered Costner to pay her $129,000 per month (he initially wanted to pay $51,900), and she recently went to court requesting that the amount be increased to $161,000 per month (she initially wanted $248,000 per month). Baumgartner filed for divorce in May after 18 years of marriage.

In court documents filed Wednesday and obtained by ET, Costner called Baumgartner's claim that he "steadfastly refuses" to pay child support sufficient to meet the children's reasonable needs as "demonstrably false and purposely inflammatory." Costner then insisted that he and Baumgartner "simply differ on what 'reasonable needs' means in the context of child support." Costner also didn't mince words when describing her "baseless character attacks" on him.

"Christine's relentless 'jihad' against Kevin's character adds a level of animosity to this proceeding that is wholly unnecessary," the court documents state.

Costner has proposed paying Baumgartner $63,209 per month in child support, and he's adamant that the monthly figure fully meets the reasonable needs of their children. He implored the court that any child support "greater than that amount is simply disguised spousal support."

The hearing is set to resume Friday.