Yesterday we told you that Katy Perry's concert, scheduled for 7:30pm at Van Andel Arena in Grand Rapids, was postponed due to illness.  Today we have more details.

The show has been rescheduled for Thursday, December 1.  Tickets from Sunday's postponed show will be honored.  Fans may also receive a refund at the point of purchase if they choose.

The show was postponed due to "an upper respiratory illness".  According to her tweets, Katy hadn't been feeling well since at least last Tuesday.

Here's a few of Katy's tweets over the last week.

(9/6)  I don't if it's the drinks or the chlorine water but mom's ready for a cat nap!

(9/8)  Hey kids. Mothers not feeling too cute tonight. That means I'ma need u to sing LOUD okay?!

(9/10)  Alright childrens! I'm gonna throw myself on stage tonight... snot, sweat, tears and all. Sing loud, I'ma need it!

(9/11)  Sick in bed and watching the memorials today. Taking time to remember all the lost & all the heroes.

It's very disappointing to have the show postponed, but I think we'd all like to see Katy get herself well and put on the best show she can.  Looking forward to her visit on December 1.