Prince Andrew appeared to have controversially added convicted Libyan gun smuggler, Tarek Kaituni to the 100-strong guest list.
Over the year, the Duke has faced backlash for his association with convicted paedophile Jeffrey Epstein, particularly after the billionaire committed suicide in jail earlier this year.
However, he appeared to have kept his head above water - likely due to the support of Fergie, who according to 7 News, joined the Prince on a trip to Spain when the scandal resurfaced.
According to The Sun, Prince Andrew – who married the former Duchess of York in 1986 before they divorced in 1996 – was said to have shared several tender words about his ex-wife.
A source told the publication that Andrew was heard telling guests that Fergie had been "there for him in his hour of need," sparking questions of why the couple haven’t remarried.
"Andrew was telling people how much Sarah had been there for him in his hour of need," the source said.
"It’s a mystery to many of their friends why they don’t re-marry.
"They seem so made for each other and must be the happiest divorced couple in the world!”
What’s more, Prince Andrew (the second-youngest child of Queen Elizabeth) was said to have insured Fergie was the epicentre of all the festivities at her 60th birthday bash – he even made her favourite Laurent Perrier pink champagne "flowing like water."
Another source said Fergie deeply appreciated the tribute from her husband.
"Sarah was in top form and was clearly moved that so many good friends had turned up for the bash," they said, according to Express.
Earlier in the week, Fergie appeared to be excited about her 60th birthday.
"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 earlier this week.
Prince Andrew was the first person to wish his ex-wife a happy birthday on social media.
Prince Andrew posted the following message on both Twitter and Instagram:
"Wishing Sarah Ferguson a very Happy 60th Birthday!"
On Instagram, the Duke of York shared three pictures of Fergie with her family, including her daughters, Princess Beatrice and Princess Eugenie, and their respective partners, Jack Brooksbank and Edoardo Mapelli Mozzi.
In recent years, Sarah has appeared at more events with the Royal Family, such as Royal Ascot, and referred to Prince Andrew as her soulmate - sparking rumours that she has reunited with her former love.
Fergie confirmed that she was living with Prince Andrew again in July this year.
While addressing a group of people, she said "Yes, I do live in Royal Lodge with my handsome prince, who is the best-looking prince of the whole darn lot, you know, there you go,” she says in the clip.
Though she didn’t name the prince in the clip, it is evident that she is speaking about her ex-husband.