The Legally Blonde star, 46, shared a heartwarming photo on Instagram Sunday embracing her 18-year-old son, sweetly noting that the hug from Deacon "made [her] whole year."
In the cute selfie, Deacon wraps his arms around his mom's shoulders as the pair smile for the camera.
The teenager, whom Witherspoon shares with ex Ryan Phillippe, later replied in the comments section, "Miss you so much!!"
His older sister Ava Phillippe, 22, also added, "love this, love you two ❤️"
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Deacon Phillippe Instagram
Last month, it was announced that Deacon will make his acting debut in the upcoming, penultimate season of the hit Netflix comedy Never Have I Ever. He'll guest star as Parker, a newcomer in the orbit of Devi Vishwakumar (Maitreyi Ramakrishnan).
According to a release from Netflix, Parker is a member of a rival debate team from a rich private school. His lifestyle offers him certain advantages that allow him to coast as a student, so he's always ready to party.
And Deacon will have personal experience to draw on for the role — he just graduated from high school himself!
In June, Witherspoon and Phillippe came together to celebrate their son's high school graduation with an intimate backyard commencement, in which Dad "played principal" and the lone grad tossed his cap into the pool.
The family posed for a sweet graduation photo by the pool as Deacon displayed his diploma and his dad rocked a cap and gown of his own.