It was an understandably emotional day for Prince Harry yesterday, who was moved to tears after seeing his bride Meghan walk down the aisle.
And the royal, 33, was also overcome by emotion while listening to the choir sing Guide Me, O Thou Great Redeemer, which was one of Diana's favourites, the Daily Mail reported.
Harry and Meghan chose to include the hymn as a tribute to Diana, after it was performed at her funeral at Westminster Abbey 20 years ago when the prince was just 12-years-old.
The royal managed to maintain his composure throughout, but seemed to wipe away tears as the closing bars of the hymn were played.
Harry admitted in an ITV documentary last year that he had only cried twice over his mother's death.
"The first time I cried was at the funeral on the island," he said, referring to Diana's private burial at Althorp.
"And only since then, maybe once more. There's a lot of grief that still needs to be… to be let out."
The royal and his bride Meghan Markle made sure to include tributes to his late mother throughout their big day on Saturday.
Meghan carried a bouquet containing forget-me-nots, specifically chosen as they were Diana's favourite flower.
"The couple specifically chose them to be included in Ms. Markle's bouquet to honour the memory of the late Princess on this special day," a spokesperson for Kensington Palace said.
The late royal's sister Lady Jane Fellowes gave the only reading of the service, the eighth chapter of the Song of Solomon.
Meanwhile, Diana's close friend Elton John - who performed at her funeral - was asked by Harry to play a medley of his best-loved hits during the couple's lunchtime reception.
Meghan's engagement ring, designed by Harry, features two stones from Diana's personal collection.
The bride also wore one of her late mother-in-law's pieces for last night's evening reception, flashing Diana's aquamarine ring as the couple departed for Frogmore House.
How Harry bottled up his grief over Princess Diana
In interviews last year to mark the 20th anniversary of his mother's death, Prince Harry admitted how bottling up his emotions made a devastating impact on his mental health.
He had, he confessed, been 'very close' to a complete mental breakdown on numerous occasions.
The turmoil over his emotions saw him endure two years of what he described as 'total chaos' before seeking professional counselling on the advice of Prince William.
He disclosed that he had only begun to address this grief when, at the age of 28, he had felt himself to be "on the verge of punching someone" while also facing anxiety when carrying out official engagements.
In a video filmed for the Heads Together campaign last year, Harry and William admitted that they hadn't spoken to each other enough in the past about their mother's death.
Harry said: "We've never really talked about losing a mum at such a young age.
"I always thought, what's the point of bringing up something that's only going to make you sad. It ain't going to change it. It ain't going to bring her back."
He is now an outspoken mental health advocate along with his brother William and sister-in-law the Duchess of Cambridge, who are aiming to change the conversation around mental health with their Heads Together campaign.