Elton John and John Lennon working together inside the Record Plant Studios in New York City, August 1974. Photo by Bob Gruen. John Lennon was working on his solo album Walls and Bridges when Elton dropped in to help out. Elton ended up contributing piano and harmony vocals to a catchy track called Whatever Gets You thru the Night. While they were tracking it, Elton looked at John and made a bold bet: if the song hit No. 1, Lennon had to come out and perform it live with him at Madison Square Garden. John didn't think it stood a chance at the top spot, so he happily shook on it. Well, the song became a massive smash, hit No. 1, and John kept his word—resulting in his final major live performance on Thanksgiving night later that year.