Taking to Instagram, the 59-year-old shared a series of photos taken of her former flame at the Chelsea Flower Show.
And her followers were quick to comment and praise the pair's friendship.
"You and Andrew should totally get remarried!! You’re still clearly in love with each other!!," one fan wrote.
Meanwhile, another shared: "I would love to see you & Andrew together again, whats happened is left in the past."
Sarah's recent post comes just days after she attended the wedding of Lady Gabriella Windsor and Thomas Kingston along side her ex.
The pair were all smiles as they arrived at Windsor Castle together.
Earlier this year, a royal insider told New Idea: "Fergie and Andrew are desperately in love – probably more than the first time around – but they want to keep their love to themselves for a little while longer before going public."
The source continued: "Fergie and Andrew are closer than ever and while they’ve long denied rumours of a rekindled romance, it is common knowledge within the palace that they are together and are making definite plans for the future."