Joe Cocker and John Belushi twinning on SNL in 1976.
Source: Reddit
Hell yes! Dueling Cockers. This is from an Oct 2nd, 1976 episode of Saturday Night Live. It's the character impression that pushed John Belushi ahead of the pack with this SNL cast mates - and made him a breakout star. Joe Cocker was the musical guest and Belushi performed alongside of the contorting singer with his best Joe Cocker impression - as the two performed the song, Feelin' Alright.
This wasn't the first time Belushi played Joe Cocker. This was a role that he perfected in 1973 when he was a member of the National Lampoon live show, Lemmings.