David Arquette celebrates daughter Coco's 21st birthday with a sweet throwback photo, saying that he's "so honored to be your ...

The daughter of Christie Brinkley and Peter Cook celebrated her 21st birthday Tuesday. And her supermodel mom had an extra special happy birthday to wish her, for all of Instagram to enjoy.

Tim McGraw and Faith Hill celebrated their daughter Audrey's 21st birthday on Tuesday (Dec. 6) with separate posts sharing stories and memories about the youngest of their three girls.