Reese Witherspoon has thrown a graduation party for her kids.

The 42-year-old actress - who has daughter Ava, 18, and son Deacon, 14, with ex-husband Ryan Phillippe, as well as Tennessee, five, with spouse Jim Toth - has taken to her Instagram account to celebrate her two oldest children graduating from school, giving her followers a behind-the-scenes look into her family's big day.

Alongside a photograph of Ava and Deacon in their graduation gowns, Reese wrote: ''Congratulations''

The image also showed a sign reading ''You did it'' attached to the fence surrounding their swimming pool.

The 'Legally Blonde' actress - who divorced Ryan in 2007 - also shared part of the menu from their day of celebrations.

Over the weekend, Ava took to social media to mark her graduation, sharing a throwback snap of her first day of school.

Celebrating the landmark moment in her life, the aspiring model wrote: ''I graduated high school! (here's what I looked like at the beginning of it). (sic)''

Reese previously admitted to leaning on Ava for help with her youngest son Tennessee.

The Academy Award-winning star - who married Jim, Tennessee's dad, in 2011 - revealed that his teenage daughter has provided her with some much-needed support in recent years.

She shared: ''The kids all have funny and unique relationships with each other. Ava is like another parent to Tennessee, like his other mother.

''I think sometimes he even gets confused.''

Ava has already amassed more than 650,000 followers on Instagram.

And her dad Ryan is proud that his daughter's social media accounts are interesting so many people - although he attributes much of her popularity to Reese's career success.

He previously said: ''She has an incredibly famous mother and a moderately famous father, but that's how that works.

''And also social media is largely driven by the youth and the associations made within that group. She's incredibly talented.''