After John Lennon left The Beatles, he didn’t frequently do performances. He never even went on a full tour. However, John Lennon performed in front of a large audience after losing a bet to Elton John. John recalls the performance being his first in a while, and he was “physically sick” before getting on stage.
John Lennon and Elton John became good friends. The two collaborated on two songs: A cover of “Lucy in the Sky With Diamonds” by Sir Elton and Lennon’s “Whatever Gets You Through the Night.” Lennon helped Elton with his cover of the famous Beatles song but was credited as Dr. Winston O’Boogie, with Winston being his middle name. The song was commercially successful and reached number one on the US Billboard Hot 100.
Source: Ross Tanenbaum/cheatsheet.com