Sheeran wrote and recorded his part at Russell Crowe's house. The Brit revealed to Billboard
he was travelling in Australia when he was contacted about a possible collaboration. "I get an email from Paul Rosenberg, Eminem's manager, and he said, 'We're gonna start putting the album together, send any ideas,'" Sheeran recalled.
Russell Crowe had previously offered up his home, which is equipped with a recording studio, if Sheeran needed a place to stay, so the Shape Of You
hitmaker took him up on the offer and got to work on the track. "I used the studio at Russell's house... played the drums on it, and then played the guitar, and then recorded the thing and wrote the chorus and did the piano on it, and then sent it off and then didn't hear anything back," he remembered. "This was, like, March, 2016."
Sheeran didn't hear anything back about his contribution for 14 months. Then in May 2017 he was contacted by Eminem producer Emile Haynie. He recalled: "I was in Mexico and my mate Emile who produces a lot for Eminem is like, 'I've done some drums and stuff on the 'River' song that you wrote.' I was like, 'Oh, cool. Are you going to send it to him?' He's like, 'Oh, no. He's done his verses.'"