The music icon revealed the news ahead of Sunday's headline performance.
A tongue-in-cheek (almost literally!) hashtag is producing hilarious parody results on Twitter right now.
#IfTheBeatlesHadBeenFat Let It Be Chips— Fattykins (@ISmellLovely) June 19, 2015
...Take a sad song, and make it butter. #IfTheBeatlesHadBeenFat— Jonathan Hart (@ee_jwhart1) June 19, 2015
Sergeant Pepper's Lonely Gastric Band #IfTheBeatlesHadBeenFat— Judas Iscariot (@Judasontwitt) June 19, 2015
Twix and Stout #Ifthebeatleshadbeenfat— Peter Smith (@Redpeter99) June 19, 2015