Williams described the 'Lego House' singer as a pleasure to work with, after they collaborated on Sheeran's current single 'Sing', reported Digital Spy.
"I think that he is an anomaly, he's not easily describable, in the sense that he's not normal," Williams said.
Williams added: "Sheeran is different, he thinks about things different. He has a different perspective. It's a pleasure to work with him because I'm able to work with a different type of human being, who just sees things differently, and I'm able to learn and sponge things from him too."