English rock band Black Sabbath has postponed their two Alberta concert dates in Calgary and Edmonton this weekend due to lead singer Ozzy Osbourne coming down with 'extreme sinusitis,' the group posted to social media, just hours before their Saturday Rexall Centre show in Edmonton.

"Due to extreme sinusitis with Ozzy Osbourne the shows in both Edmonton and Calgary have been postponed. Details regarding rescheduled dates will be announced as soon as they are available," the group tweeted at 5:13 p.m. MT

The group assured fans their tickets would be honoured at the rescheduled date, which has not been set yet.

Some on Facebook were not happy.

"I travelled 4 hrs this afternoon and we have a $300 hotel room and booked this time off," Bo Gawryliuk commented on the group's post announcing the delay.

Facebook comment

Some fans unhappy with the sudden cancellation of Alberta dates of the Black Sabbath The End tour (Facebook)

"I left at 2 pm and they announce this now? I can't come whenever they say, I'm out about 2 grand!!! Thanx for the last minute notice," he said.