The outdoor Glastonbury fest is a cornerstone of Britain's music calendar. But it has yet to sell out this year, in contrast to past years when tickets were snapped up within hours.
Gallagher, whose band headlined the festival in 1995 and 2004, said rap was to blame.
"If it ain't broke, don't fix it," Gallagher said in an interview, an audio of which was posted to the British Broadcasting Corp.'s Web site Monday. "If you break it, people ain't gonna go. I'm sorry, but Jay-Z? ... No chance."
He explained that the inclusion of a hip-hop act went against the festival's tradition of guitar music, adding: "I'm not having hip-hop at Glastonbury. No way. No. It's wrong."
Glastonbury Festival co-organizer Emily Eavis said the 38-year-old festival had a long history of attracting rap acts, including Cypress Hill and the Roots.
She said the media stir over Gallagher's comments revealed an "innate conservatism" in some parts of British society.
"There is also an interesting undercurrent in the suggestion that a black, U.S. hip-hop artist shouldn't be playing in front of what many perceive to be a white, middle-class audience. I'm not sure what to call it, at least not in public, but this is something that causes me some disquiet," she said in an article published Tuesday in The Independent newspaper.
Eavis said she thought Jay-Z was "absolutely the right act" for the festival.
