Lollapalooza Colombia has been forced to cancel its inaugural music festival, after a key headliner -- rumored to be Rihanna -- dropped out unexpectedly.

Apologizing to ticket holders, who are being offered a refund following the news, festival organizers posted the following statement in Spanish on the music festival's website: "The organizers wish to express their deep appreciation to all the fans who supported the festival since day one, as well as the sponsors and the media partners. We hope to return in the future to realize this first edition of Lollapalooza in the country."

While Lollapalooza has not specified which major act pulled out, without enough time for the event to find a replacement, have speculated it is superstar Rihanna who canceled her performance, due to concerns about the Zika virus.

While Rihanna has not yet officially cancelled her performance, reports that her reps did not immediately respond to the outlet's request for comment on Sunday.

Lollapalooza 2016, which was to take place Sept. 17-18 in Bogota for the first time, was also set to feature Disclosure, Lana Del Rey and Wiz Khalifa as part of its line-up this year.