Reese Witherspoon is in celebration mode: Her youngest child, son Tennessee Toth, just turned 10.
The "Legally Blonde" actress, 46, took to Instagram on Monday to mark her little one's special day.
"Happy 10th Birthday to my wonderful boy, Tennessee!!" she wrote in the caption of her post.
"Your brilliant curiosity and endless energy make me smile every day! I'm so lucky to be your mama. I love you buddy!" she continued. "Tenn turns 10!"
In addition to the heartfelt message, Witherspoon also shared a photo of Tennessee looking like a movie star, rocking sunglasses and wearing a blue polo as he stands against a sparkly background filter.
Amid the slew of comments sending Tennessee well wishes for this birthday milestone was a message from "Buffy the Vampire Slayer" actress Sarah Michelle Gellar, Witherspoon's former "Cruel Intentions" co-star.
"Happy bday Tenn!!!" she wrote. "Double digits!!"
Witherspoon shares Tennessee with husband Jim Toth, and is also mom to daughter Ava Phillippe, 23, and son Deacon Phillippe, 18, both of whom she shares with ex-husband Ryan Phillippe.