Two London Underground buskers are set to meet the Queen at Buckingham Palace.
A cross-section of performers are attending the event
Opera singer Angelina Kalahari and harpist Peter Murphy are due to attend a royal reception - a celebration of music's contribution to British life.
They will join a host of music stars including singers Katie Melua and Phil Collins and musicians Eric Clapton and Jamie Callum at the "Music Theme Day".
Since the scheme began in 2003, more than 600 buskers have shared 38 pitches across London's Tube stations.
Mr Murphy, a 48-year-old from Maidstone in Kent, said: "I am very chuffed to be asked to attend such a prestigious event.
"I have been busking now for 15 years after leaving my job as an accountant and just enjoy being able to play music every day."
A spokesman for Buckingham Palace said a cross section of people from the music industry were invited from buskers to chart toppers because they all have a role to play in entertaining through music.