The Queen is "excited" about her upcoming 90th birthday celebrations, her grandson Peter Phillips has told ITV News.
The son of Princess Anne was speaking to correspondent Dan Rivers as it was announced that tickets for The Mall street party will cost £150.
Labour MP for Hackney Diane Abbott was among those to criticise the move to ticket the event and the cost.
Ten thousand guests - the vast majority of which will be representatives from charities and organisations linked to the Queen - will attend the Patron's Lunch event, something the royal said was a "tad daunting".
He said the party - held on a weekend of national events from 10-12 June - was intended to have a carnival atmosphere, with "as many people young and old getting involved in the celebrations" as possible.
Celebrating the Queen's lifetime dedication to service
The Patron's Lunch is intended to honour the Queen's lifetime dedication to service, as well as marking her patronage of more than 600 charities and organisations.
During the event, a carnival parade will travel through The Mall to entertain the guests, and the Queen and Duke of Edinburgh will also take to a stage to listen to speeches marking the occasion.
They will later join Prince William and Prince Harry, joint presidents of the event, in the royal box for part of the day.
How to get tickets
The majority of tickets for the Patron's Lunch have been allocated to the hundreds of Queen's patronages - but they will be allowed to sell 40% of these to raise money.
A ballot will open to the public in February for a minimum of 1,000 tickets, and winners will then be able to buy them from the event's website.
The Queen's 90th birthday weekend
Here are the events due to take place on the weekend of the Queen's 90th birthday:
Friday, 10 June: A service of thanksgiving attended by the Queen and Duke of Edinburgh will be held at St Paul's Cathedral
Saturday 11 June: Trooping the Colour ceremony, also known as the Queen's Birthday Parade, staged in Horse Guards Parade
Sunday 12 June: Patron's Lunch street party on The Mall