The band was created by Albarn and Tank Girl artist Hewlett in 1998 and features four animated characters.
Albarn told The Times: "There are 13-year-old Gorillaz fans who haven't got the foggiest idea who Jamie and I are.
"The band is the band that you see in the videos and the artwork. You could have a Gorillaz show without Jamie and me."
He added: "It's about the sound, isn't it? Within the general sound of Gorillaz a lot of things are possible - different vocalists, etc - and it still sounds like a Gorillaz song."
Gorillaz released third album Plastic Beach on March 8. It features vocals from Snoop Dogg, Bobby Womack, Lou Reed, Mark E. Smith and others.