Prince Harry and Meghan Markle announced their engagement to the world in November 2017, but they had already enjoyed a much more private celebration with their friends and family.
The Duke and Duchess of Sussex hosted an incredible engagement party where they chose unconventional costumes which they revealed for the very first time in their bombshell Netflix documentary, Harry & Meghan.
WATCH: Insider details about Prince Harry and Meghan's twinning engagement party outfits
After detailing their engagement in the gardens of Kensington Palace near their former Nottingham Cottage home, their friend Lucy Fraser recalled: "They were so happy and they were going to keep it quiet because it was going to be announced a few weeks later."
Instead of opting for glamorous ensembles, as they did at their engagement photocall and official engagement photos, the couple opted for much more relaxed outfits that reflected their humour.
TRENDING: Prince Harry's reaction when Meghan Markle picks between him and Prince William in old clip: SEE
The Harry & Meghan Netflix docuseries shared a photo of the royal proposing
"So we had a little engagement party and everyone was dressed in animal onesies. Meghan and Harry were in matching penguin onesies because penguins mate for life and they were so sweet. And we had so much fun," Lucy added.
Speaking of his proposal, which was originally thought to take place inside their property, Harry explained: "I did pop a bottle of champagne while she was roasting a chicken and that kind of slightly gave the game away.
The Duke and Duchess got engaged in the gardens of Nottingham Cottage at Kensington Palace
"She was like, 'You never drink champagne, what's the occasion?' And I was like, 'I don't know, I just had it like, lying around,'" he joked, adding that they shared the special moment with her dog Guy whom she had flown over from America.
"In the middle of the walled garden, overlooked by the staff flats, I got 15 of those electric candles," Harry continued, while Meghan admitted: "He told me not to peek," before filming herself in hushed tones telling a friend: "It's actually happening!"
The couple announced their engagement in November 2017
While no photos of the penguin onesies have been released, the documentary shared a picture of the royal kneeling on a blanket holding a ring box in one hand and Guy's collar in the other while a bunch of white roses sat on the floor in front of him.
"Of course, I got down on one knee," he said, before the newly engaged couple grinned as they posed for a candlelit photo alongside Guy.
NOW READ: Inside Prince Harry and Meghan Markle's secret wild night before relationship went public
Planning your wedding? Sign up to HELLO!’s Bride Guide newsletter for expert advice, budget help, wedding inspiration and real life stories delivered straight to your inbox.