Glastonbury viewers left baffled as Sir Paul McCartney 'covers' the 'Postcode Lottery Song'

He played an emotional set lasting for more than two hours on the Pyramid Stage at Glastonbury Festival including The Beatles and Wings classics such as Hey Jude, Something , Lady Madonna, Let it Be and Live and Let Die. However some fans were left confused as they thought Sir Paul McCartney had added a bizarre 'cover' to his headline performance.

Sir Paul took to the piano to sing Let 'Em In, which many people now recognise as the song from the People's Postcode Lottery advert. Let 'Em In is a song from Paul's rock band Wings from their 1976 album Wings at the Speed of Sound and the version in the ad is by soul singer Billy Paul from 1977.

Featuring the lyrics "someone's knockin' at the door, somebody's ringin' the bell" the song is part of the People Postcode Lottery's Knocking At Your Door campaign. @kelsreeves tweeted: "I just asked hubby why Paul McCartney was singing the postcode lottery advert. Never knew it was a real song."

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@Lorimoz said: "I didn’t know that 'someone’s knocking on the door, someone’s ringing the bell' was an ACTUAL SONG by Paul McCartney. I only know it from the Postcode lottery advert."

@afashionoddity tweeted: "Paul McCartney covering the postcode lottery ad is the highlight of his glasto set for me." And @emmixbowles wrote: "You’re lying if you didn’t think Paul McCartney was playing the postcode lottery theme song."

@DFTPNK02 admitted: "I was today years old when I found out the Postcode Lottery song was originally done by Sir Paul McCartney." And @theSOWilliams wrote: "It was today I discovered that that was a Paul McCartney song."

@jonathanland91 asked: "How have I only