The singer brought an end to the show in front of the Lincoln Memorial Reflecting Pool with her hit Firework, which culminated in – yes, you guessed it – a load of fireworks going off in the distance behind her.
As well as her performance, it was the moment immediately afterwards, which was captured by her partner Orlando Bloom, that had everyone talking.
In the clip, which the British actor shared on his Instagram page, Katy can be seen holding her pose and beaming with pride as fireworks fill the sky behind her.
As the display ends, Orlando, who has a young daughter with Katy, walks towards the singer and kisses her.
“That was awesome baby. Great job,” he tells her.
“I love you,” she replies.
Sharing the footage, the Pirates Of The Caribbean star captioned it: “One day our little girl will grow up and see her mother play her part in a moment in history that we hope will heal, we hope will unite, we hope, we love.
“One proud partner here with a tear of joy.”
Tom Hanks hosted the star-studded event from Washington D.C. following the official transfer of power to President Joe Biden and Vice President Kamala Harris.
The Forrest Gump star addressed the American people at the start of the show telling them: “In the last few weeks, and the last few years, we’ve witnessed deep divisions and a troubling rancour in our land.
“But tonight we ponder the United States of America, the practice of our democracy, the foundations of our republic, the integrity of our Constitution, the hopes and dreams we all share for a more perfect union.”
Following his intro, many viewers pointed out that it had eerie similarities to a scene in The Simpsons Movie, which predicted the Hollywood star would make a televised speech in a moment of “national chaos” 14 years ago.
“The US government has lost its credibility, so it’s borrowing some of mine,” he says in a scene from the animated film.
As well as Katy Perry, the presidential celebration featured a slew of performances from the likes of Foo Fighters, John Legend, Bruce Springsteen, Demi Lovato, Justin Timberlake and Jon Bon Jovi.
The music stars performed from different locations across the US, as the inaugural events are intended to minimise the risk of further Covid-19 spread.
Watch Katy’s full performance below: