Sir Paul McCartney will never forget the Beatles.

The iconic musician, 77, dropped by Global’s “The Late Show” on Monday to promote his new book Hey Granddude! The appearance is particularly timely as the 50th anniversary of Abbey Road is on Thursday, Sept. 26.

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McCartney told Stephen Colbert how he often dreams of his late Beatles bandmate John Lennon.

“I dream about him. When you’ve had a relationship like that for so long, such a deep relationship, I love when people revisit you in your dreams… I often have band dreams. I have a lot of dreams about John.”

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Hey Granddude! is available for purchase now.

The Late Show” airs weeknights at 11:30 p.m. ET/PT on Global.