Ed Sheeran and Eminem became pen-pals after bonding over cassette tapes.
The 30-year-old Grammy-winner and the 'Lose Yourself' rapper - who have collaborated on three songs since 2017 - are regularly in contact about their tape collections and even exchange cassettes.
Speaking on 'Later... with Jools Holland', Ed said of his special connection with the 49-year-old hip-hop veteran: “I collect cassettes and I’ve got Ray Charles and Stevie Wonder and they are quite difficult to find.
“The only person I know who collects the same is Eminem.
“We worked together back in 2017 and did two more songs in 2019.
“He collects cassettes, that’s his thing. He loves collecting. He is avid at going to find them.
“We have started having this, it’s like a very cool pen-pal thing. I got a message the other day about an LL Cool J cassette.
"He said, ‘This is the cassette which made me want to start rapping’. I sent him Van Morrison and I will send him David Gray’s 'White Ladder' next.”
Meanwhile, the 'Shivers' singer - who releases his fourth studio album, '=', on October 29 - recently revealed he was freaked out by spending the day with a "naked" pop star.
The 'Shape of You' hitmaker - who won't reveal the mystery man's identity - couldn't believe what he was seeing as the fellow celebrity stripped off at a club and "walked around" in the nude.
Ed recalled: "We were just in a club with a shower in it and I turned around and he was naked.
"I remember looking at his entourage and everyone was on their phone.
"He is naked and walking around doing stuff, gets in the shower and the hot tub naked, he gets out of the hot tub and I was like, 'Does nobody think this is weird?'
"And he puts his clothes on and then the night resumed. That was quite a strange situation."