Barack Obama's daughter spotted at Chicago festival as local artists perform together
The rapper first debuted the cover at Sasquatch! Music Festival in Washington state
US artist updated fans on who he has recently spent time in the studio with
Chvrches will perform second set in place of London Grammar
The pair performed 'The Worst Guys' together at the New York festival
The rapper sang 'Believe in Yourself' at the Sasquatch Festival in North America
The rapper celebrates the first anniversary of his 'Acid Rap' mixtape
Rapper could require surgery in order to regain full health
The rapper promises to be "100 per cent" better for his next gig
US hip-hop star unable to perform at California event due to ill health