The on-field action will be the main attraction Sunday night when the New England Patriots meet the Seattle Seahawks in Super Bowl XLIX in Glendale Arizona. But plenty of fans will tune in specifically for the start of the Super Bowl Halftime Show, which will feature Katy Perry, Lenny Kravitz and at least one as-yet unknown special guest.

The Super Bowl Halftime Show does not start at a specific time, as there’s no way to know exactly how long the first two quarters of the game will take. But halftime performers in previous years typically took the stage at around 8 p.m. ET, give or take 15 minutes or so. Perry has not said which songs she plans to perform, but gave the public a few hints Thursday during a pre-show press conference.

“I don’t think I’m so much of an expert on the game of football. But I think I can assure everyone that nothing in my performance will be deflated,” Perry said, in a humorous nod to “Deflategate,” an ongoing flap about the air pressure of footballs the Patriots provided for use in the AFC Championship Game on Jan. 18.

“A lot” of this year’s halftime show will be live, though some pre-recorded vocals will be used as well, Perry said, according to Yahoo Music. She added that she’s watched several past halftime shows to prepare for her own set, which she promised will be a “whole different show” than what she’s done in the past. Kravitz was confirmed weeks ago as a special guest, but Perry still has a surprise or two planned for Sunday.

“This guest, though, I thought long and hard about it … When you hear the first ring of the chord, jaws will drop and faces will melt,” Perry said.

Perry told ESPN The Magazine last week that her set would last for a full 12-and-a-half minutes. A record 115.3 million views tuned in for last year’s show, which featured Bruno Mars and the Red Hot Chili Peppers. NBC Sports Live will provide a live stream of this year’s Super Bowl Halftime Show.