The late journalist and television star, who passed away at the age of 74 last August, was being honoured in a special ceremony at Westminster Abbey.
Prince Charles and the Dean of Westminster
Prince Charles was greeted by the Dean of Westminster the Very Rev Dr John Hall as he arrived at the church, followed shortly by his wife Camilla, Duchess of Cornwall.
The first-in-line to the throne, 65, dressed smartly in a navy suit and black tie, while the Duchess looked elegant in a black blazer and skirt, and matching black fascinator. Sophie, Countess of Wessex donned a more unique sideways fascinator.
Camilla, Duchess of Cornwall and Sophie, Countess of Wessex
Prince Andrew was also pictured walking in with his ex-wife Sarah, Duchess of York and the couple's eldest daughter Princess Beatrice. Beatrice, 25, looked particularly graceful in a navy coat with strapped leather belt that showed off her svelte figure. The royal accessorised with a black clutch and pale charcoal hat.
Princess Beatrice, Duchess of York and Prince Andrew
The chic Pippa Middleton, who opted for a navy satin coat, was also spotted among the guests and flashed a smile as she made her way through security.
Sir David's widow Lady Carina Fitzalan-Howard and the couple's three sons Wilfred, Miles and George, who all played a part in the service, posed for photographers outside the abbey.
During the ceremony, Lady Carina and Prince Charles lay flowers on a dedicated memorial stone for the late TV mogul, situated near Poets' Corner. Sir Michael Parkinson, Joanna Lumley and BBC director general Tony Hall also gave readings.
Among the 2,000 guests, other high-profile attendees included Sir Terry Wogan, Sienna Miller, Jemima Khan, Tim Rice, Stephen Fry and Carol Vorderman.
Tributes from stars and politicians pour in for Sir David Frost.
Sir David Frost
Sir David was on board the Queen Elizabeth cruise ship when he fell ill and died of a heart attack last summer.
The veteran broadcaster, who was known for his non-aggressive, affable and effusive interview style, is perhaps most remembered for his revealing interviews with disgraced former US President Richard Nixon in 1997.
Sir David skilfully coaxed the truth out of the leading politician and after 29 hours of filming, the US President admitted to his faults, revealing that he had "let down the country".
Watch the video below...
At the time of his passing, former UK Prime Minister Tony Blair praised Sir David for his skills.
"He had an extraordinary ability to draw out the interviewee, knew exactly where the real story lay and how to get at it, and was also a thoroughly kind and good natured man," said Tony.
"Being interviewed by him was always a pleasure but also you knew that there would be multiple stories the next day arising from it. David was a great professional and a good friend."