The duo, Springsteen, 62, and McCartney, 70, were performing at Hyde Park last evening when their microphones were cut off, reported Daily Telegraph.
Springsteen greeted McCartney and said, "I've been waiting for this for 50 years."
But after singing two Beatles hits both performers were forced to leave the stage in silence after their sound equipment was turned off.
The three-day event has a nightly noise curfew imposed at 10.30 PM and Springsteen, who had been playing with his E Street Band, was due to play only from 7 PM until 10.15 PM.