Katy Perry through the years

Singer Katy Perry performs to conclude the Katy Perry Witness World Wide concert, an exclusive 4-day, 96-hour, livestream in partnership with YouTube, on Monday, June 12, 2017 in Los Angeles, California.

Singer-songwriter Katy Perry performs on July 28, 2016, during the final day of the Democratic National Convention in Philadelphia. Perry stars in a new video posted by Funny or Die on Sept. 27, 2016, in which she encourages people to get out and vote, no matter what they're wearing.

Singer Katy Perry listens to the national anthem at the Jefferson-Jackson dinner on Oct. 24, 2015 in Des Moines, Iowa. The dinner is a major fundraiser for Iowa's Democratic Party.

Katy Perry performs at Allphones Arena in Sydney, Australia on Friday, Nov. 21, 2014.

Singer Katy Perry cheers for Mississippi during a telecast of ESPN's College GamDay in The Grove at the University of Mississippi prior to their NCAA college football game against Alabama in Oxford, Miss., Saturday, Oct. 4, 2014.

Katy Perry performs on stage at "The Prismatic World Tour" at the Honda Center on Tuesday, Sept. 16, 2014, in Anaheim, Calif.

EXCLUSIVE - Katy Perry performs on stage at "The Prismatic World Tour" at the Honda Center on Tuesday, Sept. 16, 2014, in Anaheim, Calif.

Katy Perry arrives at the MTV Video Music Awards at The Forum on Sunday, Aug. 24, 2014, in Inglewood, Calif.

Katy Perry performs during "The Prismatic World Tour" at PNC Arena on June 22, 2014, in Raleigh, North Carolina.

Katy Perry performs during "The Prismatic World Tour" at PNC Arena on June 22, 2014, in Raleigh, North Carolina.

Katy Perry performs during "The Prismatic World Tour" at PNC Arena on June 22, 2014, in Raleigh, North Carolina.

Katy Perry performs during "The Prismatic World Tour" at PNC Arena on June 22, 2014, in Raleigh, North Carolina.

Katy Perry and Madonna on the summer 2014 cover of V Magazine.

Katy Perry poses with Minnie Mouse and Mickey Mouse at Disney's Hollywood Studios at Walt Disney World Resort on July 4, 2014, in Lake Buena Vista, Florida.

Katy Perry performing under the Brooklyn Bridge at the MTV Video Music Awards in Brooklyn. (Aug. 25, 2013)

Katy Perry visits "The Elvis Duran Z100 Morning Show" at Z100 Studio in Manhattan. (Aug.12, 2013)

Katy Perry at the Metropolitan Museum of Art's Costume Institute Gala benefit in honor of the museum's latest exhibit, "Punk: Chaos to Couture" in Manhattan (May 6, 2013)

Katy Perry attends LACOSTE L!VE 4th Annual Desert Pool Party in Thermal, Calif. (April 13, 2013)

Katy Perry attends the White House Correspondents' Association Dinner at the Washington Hilton in Washington, D.C. (April 27, 2013)

Katy Perry leaves a Summer of Sony 5 Edition photo call, after posing for photos to promote "Smurfs 2," in Cancun, Mexico. (April 22, 2013)

John Mayer and Katy Perry arrive at the ceremonial swearing-in for President Barack Obama. (Jan. 21, 2013)

Katy Perry performs before President Barack Obama arrives at a campaign event in Milwaukee. (Nov. 3, 2012)

Katy Perry's "Prism" album, including the song "Roar," will be released in October. (July 30, 2012)

Katy Perry and John Mayer were photographed after a dinner date at Pace Restaurant in Los Angeles. (Aug. 1, 2012)

Katy Perry attends the premiere of her "Part Of Me" 3D film in London. (July 3, 2012)

Katy Perry takes photos with fans upon arrival to the European premiere of 3D film "Part of Me ," at Leicester Square in London. (July 3, 2012)

Katy Perry in a scene from her 3D film "Katy Perry: Part of Me"

Katy Perry in a scene from her 3D film "Katy Perry: Part of Me."

Katy Perry and Russell Brand attend the 3rd Annual "Change Begins Within" Benefit Celebration presented by The David Lynch Foundation held at LACMA in Los Angeles. (Dec. 3, 2011)

Katy Perry an Kanye West rock out with "ET" on American Idol," with "ET." (April 21, 2011)

Katy Perry kicks off the North American leg of her "California Dreams Tour 2011" at the Gwinnett Center in Duluth, Georgia. (June 7, 2011)

Katy Perry attends the premiere of "The Smurfs" at the Ziegfeld Theater in Manhattan. (July 24, 2011)

Singer Katy Perry (in the yellow dress) appears on stage with models at the end of the 2010 Victoria's Secret Fashion Show at the Lexington Armory in Manhattan. (Nov. 10, 2010)

Katy Perry, left, is shown with Elmo performing in a music video called "Hot and Cold" about opposites on "Sesame Street."

Katy Perry arrives at the MTV Video Music Awards at the Nokia Theatre in Los Angeles. (Sept. 12, 2010)

Katy Perry made People magazine's 2010 list of 50 most beautiful people. (Nov. 6, 2008)

Singer Katy Perry walks backstage at Staples Center in Los Angeles during the 52nd Grammy Awards. Her gown was by Zac Posen. (Jan. 31, 2010)

Katy Perry arrives at the Grammy Awards on Sunday, Jan. 31, 2010, in Los Angeles. (AP Photo/Chris Pizzello)

Katy Perry arrives at the Grammy Awards on Sunday, Jan. 31, 2010, in Los Angeles. (AP Photo/Chris Pizzello)

LOS ANGELES, CA - JANUARY 31: Singer Katy Perry (L) and comedian Russell Brand arrive at the 52nd Annual GRAMMY Awards held at Staples Center on January 31, 2010 in Los Angeles, California. (Photo by Larry Busacca/Getty Images for NARAS)

Singer Katy Perry at the Hope For Haiti Now: A Global Benefit For Earthquake Relief telethon in Los Angeles. (January 22, 2010)

Comedian Russell Brand, left, and singer Katy Perry at the Hope For Haiti Now: A Global Benefit For Earthquake Relief telethon in Los Angeles. (January 22, 2010)

Guest judge Katy Perry, second from right, joins Randy Jackson, left, Kara DioGuardi and Simon Cowell for the "American Idol" auditions in Los Angeles.

Singer Katy Perry, 25, arrives at The Art of Elysium's third annual Black Tie Charity Gala "Heaven" in Beverly Hills. Perry has been named to People magazine's 2010 list of 50 most beautiful people. (Jan. 16, 2010)

Katy Perry and musician and American Idol runner-up Adam Lambert arrive at the premiere of Sony Pictures' "This Is It" at Nokia Theatre in Los Angeles. (October 27, 2009)

Katy Perry's 25th birthday party hosted by 42 Below Vodka at a private space in Hollywood, Calif. (October 25, 2009)

Katy Perry arrives at the MTV Video Music Awards in Manhattan. (September 13, 2009)

Singer Katy Perry attends a post-concert party at The Griffin in Manhattan. (July 28, 2009)

Singer Katy Perry performs onstage at Paper Magazine's The Beautiful People Party 2009 at the Hiro Ballroom in the Maritime Hotel on April 9, 2009 in New York City.

Katy Perry arrives at the 51st Annual Grammy Awards in Los Angeles. (Feb. 8, 2009)

Singer Katy Perry attends the NRJ Music Awards 2009 at the Palais des Festivals in Cannes, France. (January 17, 2009)

Singer Katy Perry performs at the "Scalo 76" Italian TV show on November 18, 2008 in Milan, Italy.

Katy Perry performs at the Prince of Wales in Melbourne, Australia. (October 13, 2008)

Singer Katy Perry performs during the taping of Spike TV's second annual "Guys Choice" Awards at Sony Studios in Culver City, Calif. (May 30, 2008)

Katy Perry performs during the taping of Spike TV's second annual "Guys Choice" Awards at Sony Studios in Culver City, Calif. (May 30, 2008)

Katy Perry DJs at Gallery Bar in Manhattan (May 16, 2008)

Steve Madden and Katy Perry