The concert, dubbed "Katy Perry Gives Thanks," will wrap up Perry's 122-date "California Dreams" tour, The Hollywood Reporter reported.
"I am giving thanks to all of my fans," Perry said on Friday's taping of "The Ellen DeGeneres Show."
"This is my big announcement on Ellen that no one has heard about or knows about. I played 121 shows up in to the 23rd date, and I want to finish it off by renting out Staples myself and giving a free concert to anyone in the world that wants to come to the California Dreams Tour as my last show."
Later during her appearance on the show, Perry admitted she would like to have children with her husband, British actor-comedian Russell Brand, the Los Angeles Times reported.
"If it doesn't hurt the first time," Perry said on the show, "I'll keep poppin' em out!"
Also during the taping, Perry premiered the music video for her song "The One That Got Away," KOvideo reported.
"I'm so pleased to select 'The One That Got Away' as my 6th single because this song shows a very different side of me that I haven't shown with my past singles on this record," Perry said of the song.
Perry stars in the video as an elderly version of herself longing for the missing love of her life.
The pop star is set to perform the song at the American Music Awards Nov. 20.