The BBC, which is broadcasting the event, said the Massed Bands of the Household Division opened the free show, which is a tribute to Queen Elizabeth II's 60 years on the British throne.
The concert also featured performances by Annie Lennox, Shirley Bassey, Kylie Minogue, Jessie J, Will.i.am, Cliff Richard and Cheryl Cole, as well as by boy band JLS, pianist Lang Lang, and opera singers Renee Fleming and Alfie Boe.
The monarch missed the first 90 minutes of the pop concert, but took her seat in the Royal Box at 9 p.m. BST, the BBC said.
Her husband, Prince Philip, was hospitalized Monday with a bladder infection and missed the festivities.
Buckingham Palace officials said the 90-year-old Duke of Edinburgh was transported from Windsor Castle Monday to London's King Edward VII Hospital.
"Prince Philip will remain... under observation for a few days," a palace statement said.
"He is, understandably, disappointed about missing [Monday's] Diamond Jubilee concert and [Tuesday's] engagements."
People.com said the prince stood with his family in the freezing rain for four hours Sunday to watch the queen's Diamond Jubilee river pageant.