Katy Perry is delaying the start of her Witness tour in the US because of what she calls "unavoidable production delays".
The pop star will now go on the road on September 19th, instead of September 7th as originally planned.
She says she hasn't been able to fully rehearse until this week, and also apologised for any inconvenience caused.
In a statement Katy said, "due to unavoidable production delays, major elements of my tour stage design could not be available for me to rehearse on until this week.
I’ll be spending the next few weeks taking the time to properly prepare the show to be an experience I am proud to share with you. I'm sorry for any inconvenience this causes, but hope everyone who sees the show will agree it was worth the wait."