Brian Austin Green's ex-fiancée Vanessa Marcil SIDES with his estranged wife ...

Brian Austin Green's ex-fiancée Vanessa Marcil sided with his newly-estranged wife Megan Fox, and detailed the 'complete devastation' he put her and their son Kassius through in their ongoing 13-year court battle.

The 51-year-old Daytime Emmy winner Instastoried that she 'actually has respect' for the Tennessee-born 34-year-old 'living her life for herself' and moving on with co-star Machine Gun Kelly.

Marcil - who boasts 153K Instagram followers - wrote: 'Megan finally living her life for herself is in itself a gift to her children.'

Vanessa Marcil pictured with Brian Austin Green in 2000

Megan Fox pictured with Brian Austin Green in 2014

Gloves are off: Brian Austin Green's ex-fiancée Vanessa Marcil (L) sided with his newly-estranged wife Megan Fox (2-R), and detailed the 'complete devastation' he put her and their son Kassius through in their ongoing 13-year court battle

Freedom: The 51-year-old Daytime Emmy winner Instastoried that she 'actually has respect' for the Tennessee-born 34-year-old (R) 'living her life for herself' and moving on with co-star Machine Gun Kelly (L, pictured August 5)

Freedom: The 51-year-old Daytime Emmy winner Instastoried that she 'actually has respect' for the Tennessee-born 34-year-old (R) 'living her life for herself' and moving on with co-star Machine Gun Kelly (L, pictured August 5)

Megan legally separated from the 47-year-old San Fernando Valley native for the second time in May after nearly a decade of marriage.

Brian - who ended his two-year engagement to Vanessa in 2003 - was spotted Saturday sporting a camouflage neck gaiter and checkered Vans shoes to grab iced coffee to go in Calabasas.

In 2006, Green and his former Beverly Hills, 90210 castmate began their bitter court battle for full custody of their 18-year-old son Kassius leading to him sue her in 2012 over $200K he allegedly 'lent her.'

After the Cross 3 action star's 'frivolous' case was thrown out, he decided to cruelly cut then 11-year-old Kassius from his life in 2013 and did not see him again for five years.

Marcil - who boasts 153K Instagram followers - wrote: 'Megan finally living her life for herself is in itself a gift to her children'

Marcil - who boasts 153K Instagram followers - wrote: 'Megan finally living her life for herself is in itself a gift to her children'

October 12 family portrait: Megan legally separated from the 47-year-old San Fernando Valley native (L) for the second time in May after nearly a decade of marriage

October 12 family portrait: Megan legally separated from the 47-year-old San Fernando Valley native (L) for the second time in May after nearly a decade of marriage

Caffeine fix: Brian was spotted Saturday sporting a camouflage neck gaiter and checkered Vans shoes to grab iced coffee to go in Calabasas

He ended his two-year engagement to Vanessa in 2003

Caffeine fix: Brian - who ended his two-year engagement to Vanessa in 2003 - was spotted Saturday sporting a camouflage neck gaiter and checkered Vans shoes to grab iced coffee to go in Calabasas

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