Reese Witherspoon pens down a heartfelt birthday note for mini-me daughter Ava

American actress Reese Witherspoon showered love on her 'favourite' daughter who turns 23 on Friday.

Taking to Instagram, the 46-year-old Legally Blonde star,46, shared a loved-up photo featuring herself, and her mini-me eldest child Ava in honor of her birthday.

Witherspoon, who shares Ava with ex-husband Ryan Phillippe, also penned a beautiful birthday note.

'Happy Birthday to my favorite daughter, Ava !! Every day that I get to watch you become the most amazing woman is such a gift,' Witherspoon wrote.

'Your gigantic heart, generous spirit, and endless creativity inspire me every day. I love you so much'

The actress also shared an adorable throwback photo of Ava on her Instagram Story and a recent shot from when Witherspoon and her daughter went out for dinner and drinks together.

'Can't believe this little girl....is turning 23 today! Happy birthday to the most wonderful daughter! I love you, Ava!' wrote the Big Little Lies star.

Witherspoon's famous friends sent celebratory messages to Ava in the comments of the actress' post.

'Happy birthday Ava!!!,' wrote Julianne Moore, while Zooey Deschanel dropped a string of heart-eyed emojis.