Just look at him rocking a party hat celebrating her big day with her baby doll!
"Sweet dreams my little 4 year old... I think Harper Seven has had a fun packed day with her little friends... Good night little lady," he wrote.
He also honored his baby girl by flashing back to his "favourite picture of Harper of all time."
"Four beautiful years with the most amazing little girl," he wrote. "Happy Birthday big girl…." and added that little heart emoji. Awwww!
And that's not all the love Becks has been showing lately! He recently posted this sweet message to his wife, Victoria Beckham, on their 16th wedding anniversary
"16 years ago today was our special day... 16 years on we have our beautiful children," he wrote. "Thank you for giving me our amazing little ones .... Happy anniversary."