"Was my 17th today and my grandfathers 87th two days ago," Olivia wrote.
"He is a truly wonderful man who I cherish with all of my heart, he has always supported and helped my career and I couldn’t have done it without him, so a very happy birthday to Reg. Thanks for the birthday messages they meant the world, my heart is full 💕"
Yesterday was also Meghan Markle's birthday, and to celebrate Prince Harry dedicated a sweet message to his lovely wife on Instagram.
"Happy Birthday to my amazing wife. Thank you for joining me on this adventure!", the Duke of Sussex wrote, signing off with a "Love, H".
Happy birthday Olivia and Meghan!