Reese Witherspoon, praising the actress for being "brilliant, joyful, fiery" and "thoughtful" on her 46th birthday.MORE: 7 Reese Witherspoon Book Club reads for your 2022 reading list - including her latest pickSharing a picture of her mom holding onto a bouquet of flowers, Ava left fans emotional with the sweet tribute in which she shared how "lucky" she felt to call Reese mom. WATCH: Reese Witherspoon's throwback marks big milestone"With every year, her bright light shines even brighter, and I find even more reasons to love her and a greater appreciation for all that she does," she captioned the post."Happy happy birthday to the brilliant, joyful, fiery, thoughtful, and gorgeous woman that I am lucky enough to call my momMORE: Reese Witherspoon makes major announcement: 'Dreams really do come true'"I love you ...