Alongside Kate and husband Prince William, other royal guests included Prince Harry and Princess Eugenie.
However, the Middleton family reportedly did not want Meghan Markle to attend.
In December 2018, The Sun’s royal correspondent Emily Andrews wrote: “Meghan faced some opposition from the Middleton family, who didn’t want to invite her to Pippa’s wedding last May.
“They feared Meghan’s first public appearance with Prince Harry would overshadow the bride’s big day.”
In the event, Meghan only appeared for the evening reception, after Harry made a 50-mile dash to collect her from Kensington Palace in time for the celebrations.
The lavish party included a Spitfire fly-past over the Middleton’s home village of Bucklebury, which cost an estimated £700,000.
A source at the time said: “[Harry] left as discreetly as possible and travelled with her all the way back up, showing just how serious he is about her.
“He didn’t want Meghan having to arrive along, without him alongside her, at the reception.”
The news first broke of Harry and Meghan’s romance in October 2016, when a source told the Sunday Express that Harry was “happier than he’s been for many years” and “besotted” with Meghan.
Royal expert Angela Mollard, speaking on podcast “Royals” in 2018, commented: “A private secretary phoned and said: ‘Look, the word’s out. This has leaked.’
“He apparently turned to Meghan and said: ‘Things will never be the same again.’
“He knew that. He knows what it’s like, he’s seen it with his brother, he’s seen it with his previous girlfriends.
“I can imagine he felt a little bit of sadness that that privacy had [gone].”
The future Duke and Duchess of Sussex made their first ever public appearance together at a polo match at Ascot in May 2017.
However, they waited until October to make their first official royal appearance as a couple, at the Invictus Games opening ceremony in Toronto.
Ahead of the birth of Archie last month, the pair moved from Kensington Palace to their new family home at Frogmore in Windsor.