The 31-year-old singer is due to support the 'Chained to the Rhythm' hitmaker on her upcoming 'WITNESS' concert series, and though she is ''in the dark'' about the specific reasons why the start of the run of shows has been put back, she doesn't think fans should be too upset.
Speaking about the delay - which is due to ''unavoidable production'' issues - she said: ''[I'm] in the dark... I'm sure the wait will be well [worth] it.''
When she does join the tour in January, the 'Call Me Maybe' singer is looking forward to ''some hangs'' with Katy because they always have fun together.
She told 'Entertainment Tonight': ''Her people call[ed] my people.
''It was nice and I've obviously known her throughout the years and we get along great. So it'll be a lot of fun I'm sure.
''We definitely have had some fun nights before. Tours [are] always busy. You never know how much time you have off to rest your voice, but if we can get in some partying [at] the end, I'm just, we will!''
The 'Cut to the Feeling' singer will be setting up a ''back-of-the-bus studio'' when she's on the road as it's where she writes some of her best material.
Discussing her tour essentials, she said: ''I do a lot of writing when I'm on the road.
''So I always have a little acoustic guitar with me and [a] recording gear set up, like those mini microphones and, I don't know, you can make a back-of-the-bus studio if you really have all the pieces. So that would be number one.
''And number two, I think, [a] really good, fun, light book to read. I usually go for, like, the old period pieces.''