All grown up! Reese Witherspoon shared a loving message to daughter Ava Phillippe on her 21st birthday.
The "Little Fires Everywhere" star gushed about her eldest child Wednesday on Instagram, writing a heartfelt caption beside a photo of the lookalike duo.
MORE: Reese Witherspoon talks mental health, experiences with postpartum depression"Wow! How is it possible that this little girl is now 21 years old?" she wrote. "Happy Birthday to my sweet girl who has become the most incredible young woman."
"Her kindness, her compassion, and her huge heart never cease to amaze me," Witherspoon continued. "Ava, there aren't enough words to describe how proud I am of everything you've already accomplished. I cannot wait to see ALL the Good you will put into this world. I love you so much @avaphillippe."
The Oscar winner shares Ava and 16-year-old son Deacon Phillippe with ex-husband Ryan Phillippe. Additionally, she is mom to 7-year-old son Tennessee Toth with husband Jim Toth, whom she married in 2011.
MORE: Reese Witherspoon's daughter thanks her for teaching her the value of love, ambition in Instagram postEarlier this summer, Witherspoon shared a sweet message to her husband on his 50th birthday, calling him "my amazing hubby"
"Everything you do, you put in 1000%!" she wrote. "Whether he's training for a triathlon, giving back to his community, supporting his friends, or loving his family, he gives his whole heart to so many people everyday! I [heart] you so much, JT!"