The Queen’s granddaughter attributes it to the fact she was pregnant with daughter Lena Tindall at the time.
Harry and Meghan’s wedding took place on May 19 last year.
Zara explained to the Daily Telegraph: “I was uncomfortable! My bum sort of slid over either side and Lena kicked the hell out of me for an hour.
“It just wasn’t comfy at all and it probably showed on my face.”
During the ceremony, Bishop Michael Curry gave an energetic speech which lasted 13 minutes.
Zara explained how this frustrated herm adding: “It was just the general amount of time everything was taking.
“I think my face was probably caught at the point when I thought: ‘Right, he’s going to finish now’, and then he went off on another little story, and it was like, ‘Really?’”
Anne would divorce Mr Phillips in 1992 and marry Naval officer Timothy Laurence in the same year.
The Queen’s only daughter also competed for Britain in the equestrian events at the Olympics.
Zara followed in her mother’s footsteps to win BBC Sports Personality of the Year in 2006, 35 years after Anne.
She would win a silver medal as part of the Team GB Eventing Team in London 2012.
Husband Mike won the Rugby World Cup with England in 2003.
Zara was awarded an MBE for her services to equestrianism in 2007.
She was not entitled to royal title due to not being a child of the monarch’s son.
The Queen offered titles to both Zara and her elder brother Peter but Anne and Mr Phillips declined.
Mr Phillips would also turn down an earldom.