An average of 11.2 million people in the UK watched the Platinum Party in the Palace on BBC One on Saturday.
The concert saw stars including Diana Ross, George Ezra, Queen and Elbow perform in front of a Buckingham Palace crowd including the Royal Family.
It attracted the BBC's biggest audience of the year, peaking at 13.4 million.
A huge pageant in central London and thousands of street parties across the UK are highlights of the final day of Jubilee celebrations.
Saturday evening's concert also saw speeches from Prince Charles and Prince William, with Charles paying tribute to the Queen and her reign of seven decades on the throne.
Its audience beats many other recent high-profile events - December's Strictly Come Dancing final averaged 11 million viewers; last month's Eurovision Song Contest averaged nearly nine million; and the Queen's Christmas message drew an audience of 8.96 million.
The BBC said it had a 74.3% share of the audience, adding: "The Platinum Party at the Palace on BBC One was the most watched programme of the year so far."