Katy Perry's a pop star, too. She gets it.
"The only reason I couldn't make it was I was really really swamped with work," the "Only Girl (in the World)" singer explained. "I've got an album coming out in two weeks, I have a lot going on, I just switched management...I needed to be close [to the action]."
"I was lucky enough to be able to throw her a bachelorette party," she added.
While in NYC to put the finishing touches on Loud, her fifth studio album, she's also gearing up to promote her first behind-the-scenes photo book, Rihanna.