"I love how close you all are," one fan noted.
"So true! And, you are an example of a wonderful mother," another wrote.
"You seem like a wonderful mum and it's so evident you raised amazing girls," a third well-wisher added.
It's not the first time Fergie has used the platform to pay tribute to her loved ones.
On Friday, on what should have been Princess Beatrice's wedding to Edoardo Mapelli Mozzi, the mother-of-two shared a gorgeous throwback photo of Beatrice.
"Love you my darling Beatrice. You have given me more joy than I could ever wish for," Fergie penned.
Adding: "I am so excited to celebrate yours and Edo's love when we all are out of lockdown. The most important thing is health and love and today I send it to you and all the other people that were getting married during this time... so proud of you all."
Since lockdown, Sarah has used her extra time and large platform to launch Storytime With Fergie And Friends on YouTube, where each day she reads a popular children's book to her followers.
The Duchess of York has previously penned several children's books and announced on Instagram that she would be hosting daily readings of her own, and other children's books shared via YouTube and Facebook.
Despite it being an extremely tough year for the Yorks, it seems Fergie is keen to focus on the positives.