Anna Bastow, who plays the viola, and Gerry Ruddock, who plays the trumpet, were part of the London Symphony Orchestra which was due to play in Trafalgar Square tonight from 6.30pm.
They performed three works by Tchaikovsky including the 1812 Overture and Symphony Number Four in the free concert.
They were conducted by Valery Gergiev and young musicians from the LSO’s On Track scheme for children joined them, together with students from the Guildhall School of Music.
This was the fifth successive year that the open-air concert has taken place and some 20,000 people are believed to have been in the audience.
Ms Bastow, 34, who grew up in Beverley in East Yorkshire and played for the East Riding Youth Orchestra, said: “I have played these open-air concerts in each of the five years I have been with the LSO and it is a great party atmosphere. You get classical music fans and people who just happen upon us in Trafalgar Square, which is great.
“We reach a different type of audience which is fantastic.”
Mr Ruddock, 62, who was born in Saltburn and who grew up in Redcar, said: “This is a fantastic event which I have been involved with for quite a few years now.
“There are thousands of people watching and listening and it is great to reach out to them.
“We don’t play venues such as Trafalgar Square very often so it is nice to do something different, something special. We love performing here.”