The Genesis drummer chatted with PEOPLE on Friday at the press conference for his Little Dreams Foundation and explained the failed collaboration.
"We met in London maybe three or four years ago, maybe longer, because she wanted to write with me and I was very flattered, but I didn't know who she was, because I had been living under a rock," he says with a laugh. "I quickly found out and wow … I did a crash course on Adele."
Once the rocker realized who he would be working with, the two moved forward very quickly.
"We met in London, she was very very sweet, I made her a cup of tea," he says. "She sat down and said 'I would love to write with you' and I said 'great' and she gave me this piece of music and I liked it and she said, 'Well, finish it.' "
From there, Collins was all in. "I took it back to New York, which is where I was living at the time, and worked on nothing else but that [music]."
Ultimately, though, he felt the music wasn't working.
"I couldn't really do justice to the bit that she had given me," he says. "And then she got difficult to find."
The partnership ended there, and it wasn't until much later that Collins learned why.
"I later found out – or just recently since she's been doing press for this new album – that it was too early for her, she wasn't ready," he says. "I was grateful for her explaining, because it does look like I didn't pass the audition."
So after all that, what does the singer-writer-producer, who recently reconciled with ex-wife Orianne Collins-Mejjati, think of Adele's now-famous album?
"I haven't listened to it. The bit that we were working on might even be on it, I don't know," he says with a wink.
That's not to say he isn't a fan. When asked who he'd like to work with in the future, he says, "Adele actually ... she's just the strongest artists to come out in recent years. I just think she just handles herself really well. She's just very smart ... She's just really good."