Reese Witherspoon shared a throwback photo and a tribute Thursday to Instagram in honor of her daughter Ava Phillippe's 22nd birthday. 

"This person is turning 22 today…" Witherspoon captioned a baby photo of Phillipe wearing a birthday hat.

The "Legally Blonde" star also shared a more recent photo of Phillippe.

"Happy Birthday to my sweet little girl…excuse me… I mean my adult daughter!!!" Witherspoon wrote. "Words can’t describe how proud I am of you. You have grown into an extraordinary person who cares so much about the world around her. I am so lucky to have you light up my life. I love you, Ava!!"

AVA PHILLIPPE LOOKS JUST LIKE REESE WITHERSPOON AS SHE STEPS OUT FOR LUNCH WITH HER BOYFRIEND

Reese Witherspoon shared photos of lookalike Ava Phillippe in honor of her daughter's 22nd birthday. 

Reese Witherspoon shared photos of lookalike Ava Phillippe in honor of her daughter's 22nd birthday.  (Photo by Dia Dipasupil/Getty Images)

Witherspoon added the hashtag, "#thisis22" to the caption.

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Witherspoon and her daughter have always had a close relationship. The actress wrote about Phillippe in a blog post back in 2018.

"I think the way Ava and I are most alike is our strong opinions and our empathy," Witherspoon wrote at the time.

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"From the time that she could speak, Ava has always had her own ideas, and I love to watch her express herself. She also cares deeply about her family and the world around her. She frequently educates me on news stories and issues young women are facing."

Witherspoon shares Phillippe and 17-year-old son Deacon with her ex, Ryan Phillippe. She also has a son, Tennessee, with her husband Jim Toth.