In response to the post, Hawn commented, "Oh! I love you, my baby girl!! Meanwhile, Oliver Hudson also remembered his mother, but instead of sharing a recent photo, the actor took the opportunity to post a legendary throwback on Instagram.
"Happy birthday day to this girl who happens to now be my mother!!!!" he captioned a shot of Hawn in a green bikini with colourful words and designs painted all over her body.
The 43-year old actor goes on to add, "And I apologize for stretching your stomach but your bounce-back was all world... I love you Ma! Keep saving the world! @goldiehawn" Oliver, jokingly added of her toned physique in the image.
Responding to her son's post, Hawn sweetly wrote, "Oh honey. I love you and my tummy that held you. It served us well! "Over the years, Kate has often spoken about the close relationship she shares with Hawn and what the Overboard actress has taught her since becoming a mother.
In addition to Rani, who Kate shares with actor and boyfriend Danny Fujikawa, she is also mom to 8-year-old son Bingham Hawn from her relationship with singer and ex-fiance Matt Bellamy and 15-year-old son Ryder Russell, from her marriage to ex-husband Chris Robinson.