The Los Angeles Times wrote in 1986: 'Some spectators said they saw her wink at Andrew beneath her veil as she vowed to 'obey' her husband.'
At this time, the British royals were not known for their public displays, so Fergie's cheeky display was incredibly unusual.
But, that's not the only time Fergie winked on her wedding day. When the newlyweds were exiting the church, a rare black-and-white photo shows Fergie, once again, doing the gesture at someone in the crowd.
More recently resurfaced footage from earlier this month, sees Fergie speak openly about her 'whirlwind romance' with Prince Andrew and the intense love she experienced on their royal wedding day as her youngest daughter, Princess Eugenie, prepares for her own big day.
The Duchess of York relieved the special moments that marked that spectacular day - from the feeling she had for her groom to their iconic Buckingham Palace balcony appearance.
Speaking to Piers Morgan, she described stepping onto the world stage as a royal wife as 'mesmeric.'
Fergie explained, 'Let me go back in time. You are taken with such a wave of energy, that it is just mesmeric, it is just extraordinary.
'And you're so in love, it's your wedding day. Like every bride's wedding day, it's a special day.
'And you've got a beautiful dress on. But you're standing there with the man you love.
'And then there are people out there who are wishing you so well. And it's just extraordinary.'
'It's just unfathomable. You can't explain it,' Fergie adds.
'And when I went up that aisle, I had - I married my man.'
Sarah and Andrew separated in 1992 after just six years of marriage and divorced four years later.
The former couple share two daughters - Princess Beatrice and Princess Eugenie.