The Duke and Duchess of Cambridge rounded off a full day on the opening leg of their trip to Germany by attending the Queen’s birthday party.

William and Kate raised a glass to the monarch at the British ambassadorial residence in Berlin.

The Duke and Duchess of Cambridge
(Chris Jackson/PA)

The Duke and Duchess of Cambridge
Kate wore a scarlet gown for the party (Chris Jackson/PA)

The Duchess of Cambridge
(Chris Jackson/PA Wire)

in a speech, the Duke of Cambridge repeated his belief that Britain and Germany will remain “the firmest of friends” despite the UK’s decision to leave the European Union.

William, echoing comments he made last year during a trip to Germany, told guests at a Berlin garden party the relationship between the two countries “really matters”.

Britain’s ambassador to Germany Sir Sebastian Wood hosted the evening but he was left a little red faced before a toast to the Queen when he spotted Kate and William were empty handed.

He told the crowd: “Oh dear. We have no glasses. This is where we do what the British say and, ‘Keep calm and carry on.'”

As the party waited and no drink appeared, he said: “No I’m sorry. I won’t carry on. There are hundreds of glasses here, can we please have one?”

The Royal couple and Sebastian Wood
British Ambassador to Germany Sebastian Wood (right) delivers a speech (Chris Jackson/PA)

The couple later mingled with guests who packed the lush green grounds surrounding the ambassador’s sprawling home in Berlin sipping Pimms and champagne.

The Duchess of Cambridge
Kate mingles with party guests (Matthias Nareyek/Pool via AP)

Earlier, thousands turned out to see William and Kate walk through the capital’s famous Brandenburg Gate, a symbol of German unification, which for many years was trapped in the No-Man’s Land between the Berlin Wall.

the Duke and Duchess of Cambridge
The Royal couple wave to the crowd at Brandenburg Gate at the start of their three-day visit to Germany . (AP Photo/Michael Sohn)

Duke and Duchess of Cambridge
William and Kate visit the Brandenburg gate accompanied by the Mayor of Berlin Michael Muller and his daughter (Julian Simmonds/The Daily Telegraph)

The Duke and Duchess of Cambridge
The Duchess wore a Catherine Walker dress (Gregor Fischer/AP)

The couple were cheered as they arrived by around 2,000 people who had stood in sweltering conditions to catch a glimpse of the royal visitors.

Duchess of Cambridge
Kate chatted with the crowd and posed for photographs (Julian Simmonds/The Daily Telegraph)

Some were lucky enough to chat to the Duke and Duchess when they went on a quick walkabout before posing for a picture with the monument in the background.

the Duchess of Cambridge
(Gregor Fischer/dpa via AP)

The Duchess of Cambridge
(Gregor Fischer/dpa via AP)