The pair went their separate ways back in May, after 18 years of marriage.
Things continue to get messy in the ongoing divorce between Kevin Costner and his estranged wife, Christine Baumgartner.
In new court docs obtained by ET, Costner alleges that Baumgartner is using "stalling tactics" to drag out the pair's already bitter divorce battle.
The Yellowstone star's legal team is slamming Baumgartner's claim that she did not understand their prenup agreement when she signed it, calling it "gamesmanship of the worst sort." As ET previously reported, things came to a head between the pair when Baumgartner refused to leave their family home in Santa Barbara, California despite a prenup stipulation that Costner claimed required her to do just that.
"Christine avoids answering many of the Requests for Admission ('RFAs') based on the claim that the ordinary words used, words like 'understood' and 'negotiation' are too vague," Costner's lawyers claim in the docs.
Baumgartner, 49, "cannot admit or deny an RFA because she does not understand the word 'understood,'" the docs continue.
In an early July filing, Costner, 68, claimed that the prenup she signed when they tied the knot in 2014 stipulated that Baumgartner agreed, in the event of a divorce, the actor would have exclusive possession and use of his separate property residences, and that she would vacate any separate property family residence she was living in within 30 days of the filing of a divorce petition.
In her response, Baumgartner stated she would not move out of the property unless Costner agreed to her child support request of $248,000 per month. At the time, Baumgartner, who shares sons Cayden, 16, and Hayes, 14, and daughter Grace, 13 with the actor, was ordered to vacate the home by July 31 and has since moved out of the Santa Barbara estate.
Costner, meanwhile, said he's willing to fork over $51,940 per month but was ultimately ordered by a judge to pay $129,000 per month in child support on a temporary basis, pending a November hearing on the matter.
While Costner's legal team says he has acted "expeditiously" in pushing their divorce forward, Baumgartner has only "thrown roadblock after roadblock up in an unjustified effort to avoid answering this discovery."
The docs continued, "Her refusal to answer these RFAs is just a stalling tactic designed to avoid admitting there the parties did not enter into any transmutation agreements."
A hearing has been set for September 6 to settle the matter -- and it's not the only one on the books. In addition to a November hearing to settle their dispute over Baumgartner allegedly removing personal items from the family home, hearing dates have been set to finalize Costner's child support payments to his estranged wife.
Baumgartner filed to divorce the actor in May, after 18 years of marriage. According to court documents, obtained by ET, Baumgartner cited irreconcilable differences as the reason for the dissolution of the marriage and listed April 11 as the date of separation.
One day after Baumgartner filed for divorce, a rep for Costner intimated he was dragged into a divorce.
"It is with great sadness that circumstances beyond his control have transpired which have resulted in Mr. Costner having to participate in a dissolution of marriage action," the statement read from Costner's rep to ET.
The statement, as it would turn out, provided the first clue that the divorce would be contentious. And in the weeks and months that followed after Baumgartner filed for divorce, the proceedings have been tumultuous, to say the least.
For a full breakdown of their longtime marriage turned messy divorce, check out the links below.