The "Go Gentle" hitmaker feels he is not up to the "quality" of pop stars like Mars and the "Thinking Out Loud" singer, reported Female First.
"There's a quality that's happening there with Ed Sheeran and Bruno Mars that I'm not reproducing. I'm not as good as that. That's where I should be.
"It's because of Ed that I wrote 80 songs for this album. The first albums I'd write 17 songs. By the 'Reality Killed the Video Star' period, I'd just smoke a load of weed and come in and try and do things - if we did, great, if we didn't, fine. So now I'm like OK, I get it," Williams said.