The 10-time Grammy victor stopped to play a few songs on the piano at St Pancras station's concourse, quickly attracting a sizeable crowd of passers-by and fans.
John Legend stunned fans by holding an impromptu gig at a London train station on Wednesday morning.
We can't wait to hear all the performances on our station pianos!
While another fan wondered who was taking up precious piano time at the station. "Do they still have that piano there?" he asked his followers, immediately triggering excitement for people in the area and disappointment for those who were unable to get to the location.