They were among scores of guests invited on board the vessel for drinks ahead of the couple's big day today.
The newlyweds looked a picture of happiness as they mingled with guests and family members - including Prince Harry and Princesses Beatrice and Eugenie.Zara and England Rugby star Mike did not hold back expressing their clear affection for each other, posing for one last kiss in front of well-wishers following their wedding rehearsal at Edinburgh's Canonbury Kirk yesterday.
The Duke and Duchess of Cambridge laugh as they leave the Royal Yacht Britannia following a pre-wedding cocktail party hosted by Zara Phillips and Mike Tindall
Zara Phillips laughs as she enjoys a cocktail party on board the Royal Yacht Britannia with fiancé Mike Tindall
Zara flashes some leg as she negotiates the steps on board the yacht before being guided down by fiancé Mike Tindall who looked smart in a blue suit and cream tieZara, who arrived at the rehearsal wearing flip-flops, jeans and a hoodie, swiftly transformed herself in a £500 tie-dye silk dress from the U.S. label Alice and Olivia for the evening celebration - although it did reveal a white mark where he bikini top had been.
Once on board the yacht, she was spotted laughing and joking with friends - many of whom were rugby player friends of her fiancé.
The couple were also joined by the Earl and Countess of Wessex, Zara's brother Peter Phillips and his wife Autumn - and of course the bride's mother Princess Anne and her father Captain Mark Phillips.
Guests were photographed in dinner suits and evening suits sipping pink champagne as the sun set over Edinburgh.
Princess Beatrice looked stunning in a purple dress and belt, while Princess Eugenie opted for a red number.
All aboard: Prince William and Kate, with Princesses Eugenie and Beatrice in red and purple with the Earl and Countess of Wessex, and Bea's boyfriend Dave Clark (centre) 
The Duke and Duchess of Cambridge make their way off the yacht with Princesses Beatrice and Eugenie, Prince Harry and the Countess of Wessex
All smiles: The Royals leave the yacht with the girls gripping the bannister as they made their way down the steps The Duchess of Cambridge looked striking in a bright green dress which she teamed with black heels.
The yacht, permanently moored in the historic port of Leith, served the Queen for 44 years - although she did not attend the festivities.
During that time Britannia carried the monarch and the Royal Family on 968 official voyages, from the remotest of the South Seas to the deepest divides of Antarctica.
Zara's parents honeymooned on the ship, cruising the West Indies in 1973.
During the pre-wedding rehearsal Zara - the Queen's eldest granddaughter - was joined by Zara's father, Captain Mark Phillips, and his second wife, Sandy Pflueger, and Zara's brother Peter Phillips.
Earlier, the bride had spent the day putting her own final touches in place.
She spent the afternoon with sister-in-law Autumn Phillips at The Balmoral hotel where she is staying in Edinburgh's city centre ahead of the wedding ceremony.
The event was the second night of drinking for many guests who had arrived in the Scottish city on Thursday, partying at the city's Tigerlily Hotel.
When the bar closed, the group headed downstairs to the hotel club, Lulu, where they declined VIP treatment and mingled with other revellers.
Spokesman David Johnston said: ‘They said they’d be perfectly happy just to have a couple of tables and were happy mixing with the rest of the crowd.’
The group drank Veuve Clicquot champagne and caipirinha cocktails as well as Grey Goose vodka with coke, lemonade, soda and Red Bull, and happily posed for pictures with other revellers.
They left at 2.45am. By 11am, 30-year-old Zara was back on the bubbly in the Bollinger Bar of the city’s £500-a-night Balmoral Hotel.
Party time: Zara looked elegant in a stunning £500 tie-dye one-shouldered dress from U.S. label Alice + Olivia as she supped on a glass of pink champagne 
Mingling: Zara is hugged by a friend as friends and family enjoy drinks in the sunshine
Princess Anne laughs with motor racing legend Jackie Stewart whilst Prince Harry catches up with his brother Prince William and his new sister-in-law 
Affectionate: Zara Phillips rests her arm on her fiancé's shoulder and then around his waist whilst the couple mingle with guests ahead of their big day todayUnlike the other royal bride, Kate Middleton, who spent her last day as a single woman enjoying a formal lunch at Clarence House with her family, Zara was knocking back £95-a-bottle Laurent Perrier Brut Rose champagne with her mates and ordering rounds of sarnies.
Accompanied by, among others, her sister-in-law Autumn Phillips, Sky sports presenter Di Dougherty and television presenter Natalie Pinkham, an old flame of Prince Harry, she spent three hours in the bar and left not long before her wedding rehearsal.
Asked by her friends if she was going to take it easy on the day before her wedding, she laughed and exclaimed ‘no!’ Zara described herself as being ‘nervous but excited and happy’ and revealed that she and Tindall had been texting each other throughout the day.
Looking noticeably thinner courtesy of an intensive pre-wedding health kick, she chatted openly about her final plans for the big day.
Asked about her hair, she said ‘nobody would be bothered’ about it but asked some of her friends to help her get ready on the day.
She revealed how the reception, which will be held courtesy of the Queen at Holyroodhouse Palace, would last until 2am and each table setting had a mini-cake placed next to it for each of her 300 guests to take home as a ‘favour’.
Rehearsing all the important bits: Zara and husband to be Mike Tindall share a kiss in front of the crowds at their wedding rehearsal
All smiles: Zara Phillips and Mike Tindall looked happy as they arrived at Canongate Kirk for their wedding rehearsal ahead of their wedding ceremony
Support: Crowds of well-wishers gathered to cheer the couple as they emerged from their chauffeur-driven JaguarWhen Autumn married Zara's brother Peter in a lavish ceremony three years ago, Zara played the role of bridesmaid, wearing a strapless, green Vera Wang gown for the occasion.
While little is known as yet of the details of the nuptials, it is likely that Zara will have asked Autumn to return the favour.
The couple will exchange their vows in Edinburgh's Canongate Kirk in front of their families and friends in a private ceremony.
The reception will be held a stone's throw from the church, in the palace of Holyroodhouse, the official Scottish home of the Queen, who has offered the use of Holyrood house to her granddaughter as a wedding gift.
Lothian and Borders Police have been working with the palace and the city council to ensure the smooth running of the wedding.
Superintendent Ivor Marshall, the commander responsible for security arrangements, said the event is expected to attract significant public interest, despite being a private affair.
Dressed down: Zara and Mike Tindall leave the church after their wedding rehearsal - Zara opting for jeans a hoodieHe said the church's location, near the Scottish Parliament on the busy tourist hub of the Royal Mile presented unique challenges. While some roads will be closed, businesses will remain open.
He added: 'The police planning unit is well versed in assisting in the organisation of high-profile and large-scale events in Edinburgh, including the recent Royal Week, the Papal visit last year and the festival.
Therefore we will be drawing on that experience to keep policing costs to a minimum and ensure it's an enjoyable day for the couple, their guests and the public.'
Officers have surrounded the kirk since yesterday and barriers line the Royal Mile in anticipation of the crowds.
The Queen and Duke of Edinburgh will join Zara's parents, the Princess Royal and Captain Mark Phillips, at the wedding.
Standing on ceremony: Police guard the gates of Canongate Kirk as preparations are made for Mike and Zara's weddingAnne's second marriage to Timothy Laurence was the last Scottish royal wedding, taking place in 1992 at Crathie Kirk near Balmoral.
Also believed to be attending are the Prince of Wales and Duchess of Cornwall, or the Duke and Duchess of Rothesay as they are known in Scotland; the Duke and Duchess of Cambridge; Prince Harry; and the Duke of York and his daughters, Princess Beatrice and Princess Eugenie.
Tindall is likely to have invited some of England's best-known rugby players who are colleagues and friends.
The event, in contrast to the recent wedding of William and Kate, will be private, and the doors will be closed to the media and public.
The wedding may be small in comparison to the scale of the last royal wedding, which was watched by an audience of 2billion internationally, but it has nonetheless been welcomed by Scotland's tourism bosses.
Mike Cantlay, who chairs tourism agency VisitScotland, said: 'The wedding represents an absolutely wonderful showcase, not only for Edinburgh but for the whole of Scotland.
'The Royal Family and Scotland have enjoyed a relationship for hundreds of years, and tourism has become a natural partner.
Latest visitor figures from VisitScotland for the Holyrood House, Edinburgh Castle, the Royal Yacht Britannia, Glamis Castle and Balmoral Castle suggest a surge of interest in the Royal Family.
Source: dailymail
