So Adorable!Reese Witherspoon Gives Her Son Deacon a Sweet Shoutout on His 13th Birthday

Reese Witherspoon's eldest son is officially a teenager!

The Legally Blonde star wished her boy Deacon a happy 13th birthday with a sweet Instagram message on Sunday, Oct. 23.

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#HBD to my sweet boy Deacon on this special day! 🎉🎂You are such a ray of sunshine in all of our lives. ☀️Your sense of humor, kindness, and joy never cease to amaze me!!! I ❤️ you! #13

A post shared by Reese Witherspoon (@reesewitherspoon) on Oct 23, 2016 at 11:29am PDT

"#HBD to my sweet boy Deacon on this special day! ?? You are such a ray of sunshine in all of our lives. Your sense of humor, kindness, and joy never cease to amaze me!!! I ❤️ you!" the 40-year-old captioned the cute pic of Deacon.

MUST SEE: This Photo of Reese Witherspoon Will Leave You STUNNED!

Reese and her ex-husband, Ryan Phillippe — who were married from 1997 until 2011 — welcomed Deacon in October 2003 and a daughter, Ava, 17, in September 1999. The actress is additionally a mom to a four-year-old son Tennessee with her new hubby, Jim Toth.

Click through the gallery below to see the cutest photos of Ava, Deacon and Tennessee!