Meghan flashed her stunning diamond ring, which was made up of three stones: one from Botswana where the couple recently went on vacation, and the other two from Princess Diana's own personal collection.
When reporters asked how Harry proposed, the prince answered: 'That will come later.'
And when questioned on how he knew when Meghan was 'the one', he responded: 'the very first time' they met.
The pair were photographed at the sunken garden (which became the white garden this year) to honour his late mother, Diana, the Princess of Wales.
Yesterday, Kensington Palace issued a statement announcing the pair were getting married after 16 months of dating:
'His Royal Highness The Prince of Wales is delighted to announce the engagement of Prince Harry to Ms. Meghan Markle.
The wedding will take place in Spring 2018. Further details about the wedding day will be announced in due course.
His Royal Highness and Ms. Markle became engaged in London earlier this month. Prince Harry has informed Her Majesty, The Queen and other close members of his family.
Prince Harry has also sought and received the blessing of Ms. Markle's parents. The couple will live in Nottingham Cottage at Kensington Palace.'
This September, the actress spoke about her romance with the prince for the first time in an interview with Vanity Fair.
'I can tell you that at the end of the day I think it’s really simple,' she told.
'We’re two people who are really happy and in love. We were very quietly dating for about six months before it became news, and I was working during that whole time, and the only thing that changed was people’s perception.
Nothing about me changed. I’m still the same person that I am, and I’ve never defined myself by my relationship.'
'It has its challenges, and it comes in waves,' the 36-year-old said of the public attention.
'Some days it can feel more challenging than others. And right out of the gate it was surprising the way things changed. But I still have this support system all around me, and, of course, my boyfriend’s support.'
'We’re a couple. We’re in love,' she continued. 'I’m sure there will be a time when we will have to come forward and present ourselves and have stories to tell, but I hope what people will understand is that this is our time. This is for us. It’s part of what makes it so special, that it’s just ours. But we’re happy. Personally, I love a great love story.'