She was seen in her Range Rover dropping off her new man at his palatial Montecito home – less than five minutes from her own house – early Friday morning after a brief trip away.
Christine’s new man is financier Josh Connor, 49; himself a divorced father of three who became legally single on January 3, 2023 – just five months before Baumgartner blindsided Costner, 68, by filing for divorce.
The couple also traveled together at Christmastime – her new banker beau flew her to Hawaii on a private jet, sources told DailyMail.com.
The pair were previously photographed laughing together on another vacation in Hawaii in July, accompanied by her daughter Grace and his youngest child Abigail, both 13, and it later emerged in court that the banker had loaned her $20,000 .
Accused by an irate Costner of having a new boyfriend, Baumgartner denied dating Connor under oath during an evidentiary hearing in Santa Barbara last August.
Bearded Connor, who was wearing a black cap and sweater teamed with blue jeans, had an overnight bag with him.
Later the same day, he was seen making a brief visit to Baumgartner’s home – buzzing himself in with his own door clicker.
And, last week, the pair were repeatedly seen popping in and out of each other’s homes – despite both having their children with them.
Sources have told DailyMail.com that the romance has been going on for some time, with the couple taking a trip to New York in December ahead of their tropical Christmas.
The insider said: ‘They’re together and they have been for a while. They spent time before Christmas together in Hawaii while Kevin was presumably in Aspen with the kids.
‘They also made a trip to New York together. She hasn’t been doing much to hide what’s going on from her friends.’
According to the source, the lovebirds met via their daughters who are themselves close friends and frequently hang out together.
As a result, Connor and his ex-wife Patricia, 48, have been pals with the Costner family for years with both living in Montecito – close to Baumgartner’s $50,000-a-month rental home and Costner’s $70m Carpinteria compound.
But Baumgartner and Connor’s once-platonic friendship has now heated up, with both the July vacation and the $20,000 loan scrutinized by Costner’s divorce lawyers.
In court, a tearful Baumgartner insisted that she and Connor are just good friends and said she shared a room with a female friend during the July vacation – which she admitted had been funded by the financier.
She was then forced to explain a $20,000 loan handed to her by Connor – $10,000 of which she said had been paid to her mother while the rest had been returned.
The glamorous blonde then had to admit that Costner had been making monthly payments of $5,000 to help her parents which had stopped when she filed for divorce.
She told court that the $10,000 had been handed over to make up the shortfall – and insisted she planned to pay it back.
Despite her denials, a bystander said the new couple had looked cozy during their July vacation, with photos showing them strolling down the beach and grinning ear-to-ear.
The onlooker exclusively told DailyMail.com: ‘She sat with the guy at a corner table. He was handsome.
They started off across the table from each other and she was laughing a lot at whatever he was saying.
‘She was showing him photos from her phone, and he moved to the seat next to her so they were both facing the water.
‘It’s hard to say if there was anything going on with them, but he did put his hand on her leg at one point that I saw. That was the only actual physical interaction.
‘Her suite is right next to the guy’s suite. He had the drinks charged to his room and they left together right before sunset.’
Baumgartner and Connor have kept their relationship under wraps since then, with the Costners settling their divorce weeks after the evidentiary hearing.
The mom-of-three had hoped to be awarded $165,000-a-month child support payments and was also fighting to overturn their prenuptial agreement which would have provided her with a one-off sum of $1.5m and no alimony.
She told court of the couple’s lavish $11million-a-year lifestyle that included a $160,000 ranch in Colorado and a sprawling beachfront estate in Carpinteria, and said she needed to rent a property for $100,000-a-month in order to provide a ‘comparable’ lifestyle for her children.
Baumgartner also claimed her lavish four-bedroom Montecito rental is ‘unsuitable’ because her sons have to share a bedroom and the luxury property lacks sea views.
Judge Thomas Anderle was unimpressed with her arguments and slashed her child support award to $63,000-a-month, down from a temporary $129,000.
Despite vowing to fight on, weeks later, Baumgartner and Costner settled their divorce – which friends later told DailyMail.com she did reluctantly.
Connor’s divorce took longer to finalize, with the banker filing to end his marriage citing ‘irreconcilable differences’ in November 2022.
The former couple finally agreed to an equal custody split over a year later, with Connor on the hook to pay ex-wife Patricia $16,500-a-month in spousal support unless she marries again.
On top of that, Patricia was awarded $16,626 in child support, although that has now been slashed by $3,325 because elder daughter Lily has just turned 20.
Younger daughter Abigail, 13, and son John, 17, remain covered by the payments with school fees shared by both parents.