"I can't tell you all how frustrating it is to read continued lies from a 50+-year-old woman on social media like she is still in high school," wrote Green, who welcomed son Kassius during his past relationship with Marcil.
Brian Austin Green is hitting back at his ex-girlfriend Vanessa Marcil after she criticized how he co-parented their son Kassius.
On Friday, the actor took to his Instagram Stories to call out Marcil over her claims that she "raised [their] son alone," while also giving a shoutout to his ex-wife Megan Fox for helping him co-parent Kassius.
Green, 49, posted a screenshot from Marcil's Instagram Stories, in which she shared a throwback photo of herself and Kassius, now 20, as a child. Responding to a follower who asked if co-parenting has been "difficult," Marcil, 54, replied, "We didn't & don't co-parent. I raised my son alone."
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Alongside her post, Green slammed his ex, writing, "So, I can't tell you all how frustrating it is to read continued lies from a 50+-year-old woman on social media like she is still in high school. She has never in her life been someone to walk the walk. Talk is cheap."
"Megan and I bust our assess to give Kass a well-rounded childhood since his mom was rarely there," he added, referencing Fox. "I'm assuming that's why she posts so much of him now. When will she just GO AWAY😂."
Green and Fox, 36, were married from 2010 to 2021. The former couple shares three sons: Noah, 10, Bodhi, 9, and Journey, 6.
Meanwhile, Green and Marcil began dating in 1999 after the two met on the set of "BH90210." The former couple welcomed Kassius in 2002, before they called it quits in 2003. The pair's split resulted in a years-long, nasty custody battle over their son.
Green and Marcil appear to have a rocky relationship, with the two taking shots at one another on social media over the years.
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Back in 2018, Marcil shared an Instagram post in which she detailed what she allegedly went through during her custody battle with Green.
"12 years ago I was served legal papers and then spent 8 years+ defending myself and my son in custody court in response to his father & his stepmother trying to get full custody (that means I would have seen my son four days a month) and then asking me to pay them child support," the actress wrote at the time, per Us Weekly. "They lost that case & a civil case asking me for $200,000."
She added that she "never asked for child support of any kind and had never tried to take time away from Kass' dad seeing him."
Marcil went on to claim that Green and his then-wife Fox "decided to completely cut" Kassius "out of their lives and his younger brothers' lives."
"Kass has never met his youngest brother and is not allowed to know where his bio father, stepmother and three younger brothers live," she said. "Custody cases hurt the children only and the truth shall set us all free. Put the kids first you guys. There shouldn’t be a 'more important parent' kids love both parents equally no matter what either parent’s struggles may be."
Green never publicly responded to Marcil's claims, but he began sharing more social posts with his son shortly after being called out.
However, several years later, the "Terminator: The Sarah Connor Chronicles" star slammed his ex over the many comments she's made about their custody battle and custody arrangement.
Per Us Weekly, Green took to his Instagram Stories in October, writing, "I just heard that my ex was claiming I spent years taking her to court and asking for child support. How was I the Respondent then??? #factsisfacts #thetruthshallsetyoufree."