It was April 18, 1975 that John Lennon did his last performance before an audience.
Above is footage of him at the Waldorf Astoria Hotel in New York City on that date performing with the band Dog Soldier.
The last time John Lennon appeared in a concert setting was when he showed up at an Elton John concert to perform a few songs at Madison Square Garden on November 28, 1974.
Check out footage of that performance below.