The Smashing Pumpkins

The Smashing Pumpkins' frontman, Billy Corgan, is thanked in the credits of Mechanical Animals and acted as creative consultant on the album. He also performed the backing vocals on "The Speed of Pain". Corgan and Manson were briefly friends, but Manson stated in an interview with i-D magazine that "Billy and I aren't really friends anymore", though he remained full of plaudits for the Chicago songwriter during the interview, calling him "a great artist" and "one of the most talented musicians I've ever worked with."

Former guitarist James Iha has reportedly contributed to The High End of Low.