A series of previously unheard interviews with John Lennon and Yoko Ono are expected to fetch up to £30,000 when they go under the hammer.
Chats with Canadian writer Ken Zeilig from 1969 feature the former Beatle and his wife discussing everything from their love for each other, their Bed-ins for Peace anti-war protests and Lennon's haircut.
The tapes were discovered by the family of interviewer Zeilig and they will be sold at an Omega Auctions event later this month.
Lennon, who was murdered in New York in 1980, married Ono the year the interviews took place.
Of their bond, he said: "That's our only worry in the world, is that we die together. At exactly the same minute, otherwise, even if it's three minutes later, it's gonna be hell. I couldn't bear three minutes of it."
Lennon, who was still a Beatle at the time of the recording, discussed the band's future.
The couple ended their relationship in 1970.
Asked what plans The Beatles had, Lennon said: "They don't, you know. The Beatles never made plans after they stopped touring.
"Plans were always made for them. And once there was nobody making plans for us, we didn't want any plans, so we don't make them."
The revered singer-songwriter mused about the future of hairstyle trends, having pioneered the mop-top look in his early Beatles career before growing his hair long while campaigning against the war in Vietnam.
Told his hair had become a "symbol" for peace, Liverpudlian Lennon said: "Well, I hope so, you know (chuckles). You see, because now everybody that complains about the length of my hair now, they're all middle-aged people with Beatle haircuts that I had in 1964, you know.
"And in, maybe, in 1984 - that dreaded year - they'll all be wearing long hippie haircuts and I'll be bald, you know. And they'll be complaining about that."
Paul Fairweather, of Omega Auctions, hailed the interviews as a "hugely important find".
The tapes will be sold by Omega Auctions during the Beatles Collection sale on September 28.