All Grown up! Reese Witherspoon Shares a New Photo of Son Deacon for His 12th Birthday — See the Pic!

Reese Witherspoon's son Deacon Phillippe is getting so big!

Over the weekend, the 39-year-old actress took to Instagram to share a new photo of herself with Deacon in honor of his 12th birthday — and we can't get over how handsome he is!

"Happy birthday to my sweet 12 year old boy! You bring joy to everyone you know. I feel so blessed to be your mom," Reese captioned the photo of herself with her dapper son.

RELATED: Reese Witherspoon Welcomes a New Addition Into Her Family — an Adorable Puppy!

The Legally Blonde star welcomed Deacon with her then-husband Ryan Phillippe in October 2003. Reese is also a mom to a 16-year old daughter, Ava Phillippe — with Ryan — and a three-year-old son, Tennessee Toth, with her husband Jim Toth.

Click through the gallery below to see more of Hollywood’s cutest kids then and now!