Legendary Queens Hip-Hop group A Tribe Called Quest has been forced to cancel a headlining appearance at today’s SanDisk Rock The Bells Festival at Fiddler’s Green, in Denver, Colorado.

The group canceled the appearance because founding group member Phife Dawg is suffering from complications due to diabetes.

“We are really disappointed we can’t perform at Rock the Bells in Denver. We are sure you understand our main concern now is getting Phife back to good health,” the group told AllHipHop.com in a statement.

Black Star featuring Mos Def and Talib Kweli has been added to the lineup to replace A Tribe Called Quest, as Phife recovers.

"We are very disappointed that A Tribe Called Quest will be unable to perform in Denver. We are glad that Phife Dawg is feeling better and wish him the best for a speedy recovery,” added Chang Weisberg of Guerilla Union. “Our fans know that we are committed to make Hip-Hop history at every show. With that said, Talib Kweli has agreed to make the trip all the way from Zurich Switzerland to join Mos Def for a very rare and legendary Black Star performance."

According to organizers for Rock The Bells, A Tribe Called Quest is still scheduled to perform at The Gorge in George, Washington on September 6.