Brian Austin Green is firing back at his ex-fiancée, Vanessa Marcil, after she claimed that she raised their son, Kassius, all by herself. In a recent Instagram Q&A session, a fan asked Marcil about how she co-parented her now 20-year-old son, Kassius, with Green. "We didn't & don't co-parent. I raised my son alone," responded the 49-year-old actress. Days later, Green posted a screenshot of her answer to his Instagram story and fired back at her claims of parenting by herself. "So, I can’t tell you how frustrating it is to read continued lies from a 50+ year old woman on social media like she is still in high school," said the "Beverly Hills 90210" star. "She has never in her life been someone to walk the walk. Talk is cheap." Green went on to praise his ex-wife, Megan Fox, who he was married to from 2010 to 2021 and played a large role in raising Kassius. "Megan and I bust our asses to give Kass a well-rounded childhood since his mom was rarely there. I’m assuming that’s why she posts so much of him now. When will she just GO AWAY," said Green.

Green and Marcil first met on the set of "Beverly Hills 90210" and began dating in 1999. They announced their engagement in July 2001 and welcomed Kassius in March 2002. The couple announced their break up in 2003. Green began dating Fox in 2004 after meeting on the set of "Hope & Faith." The pair tied the knot in 2010 and share three children together, Noah, Bodhi and Journey, along with Fox helping co-parent Kassius. Fox and Green divorced in 2021 and both are in new relationships, but Green has always spoken highly of him and Fox's co-parenting style. "We co-parent really well together. And we don't fight over time with the kids. We try and alternate holidays between Christmas Day, Christmas Eve," said Green in an interview with E!News. "But we're open to things changing. I'm very aware of—and so is she—that our schedules are insane. So when we do get time, cherish it. It's an amazing thing, and we support the other parent having time."