Reese Witherspoon's daughter makes her a ''better person everyday''.

The 'Wild' star paid tribute to 16-year-old Ava - who she has with ex-husband Ryan Phillippe - in a sweet Instagram post to celebrate her birthday.

Captioning a photograph of Ava as a young girl next to a more recent photograph, she wrote: ''Wow! My sweet girl turns 16 today!

''I am so blessed to have such a kind, compassionate, brilliant, artistic, all-around wonderful daughter who makes me a better person everyday. I love you @avaphillippe (sic)''

Meanwhile, the 39-year-old beauty recently opened up about prioritising her family and career.

She shared: ''No one's really doing it perfectly. I think you love your kids with your whole heart, and you do the best you possibly can. But, you know, right now I'm feeling sad missing my little 2-year-old, and my daughter's about to finish her freshman year of high school, and my son has a golf tournament this weekend that I hope I don't miss.

''There are some sacrifices you make, and it hurts your heart sometimes, but my kids tell me they're proud of what I've accomplished, and that just means everything. I grew up with a working mom, and I have so much respect for the things she did as a nurse and a teacher. I would never begrudge her that.''