Nathan Sykes scrapped his second solo album after his The Wanted bandmate Tom Parker revealed his brain tumour.
Tom announced in October 2020 that he had been diagnosed with an inoperable and terminal tumour, and he died in March 2022, aged 33.
And Nathan, 32, forgot about making an "obscene amount of money" with his second album to put his late friend first.
He told the Daily Star newspaper's Wired column: "After the first album [2016's Unfinished Business], I went away and wrote a second album and then obviously got the call about Tom, closely followed by the pandemic.
"So I scrapped that full album because I was like, 'I don't want any focus to be taken away from the most important thing here - Tom."
Nathan said his decision surprised those around him.
He explained: "The base level of expectation in this industry is you put yourself first.
"I walked away from an obscene amount of money, not releasing that album.
"It cost me a fortune, but I was like, 'I'm not gonna put myself first, I'm not going to put chart positions first, I'm not going to take advantage of this situation.'"
After The Wanted - also formed of Max George, 37, Siva Kaneswaran, 36, and 35 year old Jay McGuiness - announced a hiatus to pursue other projects in January 2014, Nathan restarted his solo career.
And he later reunited with his bandmates for their Greatest Hits tour in March 2022 - which gave Tom the last opportunity to perform with his friends before his death.
Nathan recalled: "A lot of people said, 'Oh, Nathan, you haven't done anything in years.'
"I mean, not to talk about the elephant in the room, but we needed that reunion for a very, very specific reason."
Nathan - who is releasing his experimental album Ultraviolet in October - said some people in the music industry are only interested in what is "cool or relevant".
He explained: "I don't want to sound like a d***, but the industry's full of idiots.
"They refuse to listen to music - they just look at what they perceive is cool or relevant.
"It's like, 'Oh my God, grow up, this is great, let people hear it!'"
