"Thank you for being you. I love you to the moon and back."
Fans took to the comment section to express their joy over the heartfelt message.
"Aww, such wonderful pictures!❤️ Happy Birthday to your Mum," wrote one fan.
"Happy birthday To you lovely mum. I hope she is having a wonderful day," wrote another royal follower.
Fergie's ex-husband Prince Andrew also took to Instagram to express a very public wish for Sarah Ferguson's birthday.
Prince Andrew posted the following message on both Twitter and Instagram:
"Wishing Sarah Ferguson a very Happy 60th Birthday!"
The second photo in the post showed the former Duchess of York with the children supported by Street Child UK (a charity that she is the patron of).
Fergie is excited about her new milestone.
"I think it's really important that my life is beginning at 60, I'm so excited by it," she told Hello UK at an event for Street Child.