Kate Middleton is the wife of Prince William, 35, the eldest child of Prince Charles, 70, and second-in-line to the British throne.
The Duchess of Cambridge married into the Royal Family in April 2011.
The ceremony was watched by millions as the couple, who had been together for three years, tied the knot.
Meghan Markle, on the other hand, married Prince Harry, 33, last month.
The couple had been together over two years after being set up by friends.
Meghan, a proud feminist, was an actress in cable show Suits, in which she played the main love interest.
Now known as the Duchess of Sussex, she had her first solo official visit with the Queen this week.
Kate waited nearly a year for her first solo trip with the Queen, which took place in March 2012.
The Duchess of Cambridge visited Leicester on the first date of Queen Elizabeth II’s Diamond Jubilee tour.
How do photos of the two occasions compare?
Meghan received an honour that Kate did not on her first day out with Her Majesty.
She travelled overnight on the Queen’s private train.
The Duchess of Sussex and the Queen were all smiles as they stepped off the vessel.
Meghan Markle wore a cream Givenchy dress and contrasting black accessories.
Meghan and the Queen were later seen giggling and chatting like close friends during the day.
A body language expert analysed Meghan Markle and the Queen in Cheshire.
Kate Middleton wore a formal green outfit and a hat for her visit trip with the Queen.
The were a more formal air to the pair’s day out.
Kate and the Queen chatted politely, and one famous image showed Kate Middleton laughing heartily as the Queen appeared to crack a joke.
Meghan Markle and Prince Harry attend his cousin’s wedding today.