Perry shined in semi-sheer champagne gown adorned with beaded flower embellishments while walking the red carpet at the L.A. Live Event Deck.
She also stopped and smiled for the cameras alongside Frozen star Josh Gad and Drew Barrymore, who looked classically elegant in a long, black ensemble.
Barrymore was honored at the event as one of the recipients of the Children's Hospital Los Angeles's Courage to Care award, along with The Billy and Audrey L. Wilder Foundation and The L.A. Kings hockey team.
ET's Lauren Zima caught up with Perry at the gala, where she opened up about why she felt it was important to come out and support the hospital.
"I had a life-changing experience of my own when I got to visit the Children's Hospital in December," Perry, 31, explained. "I got to see their music therapy program, which is basically where a bunch of musicians come and play to patients. They play to premature babies in the NICU up to adults, all of it."
"I had such a profound personal experience that I was like, 'Of course, whatever you need. If I can help you raise money or funds or get eyeballs to the Children's Hospital, I'll do it,'" she continued. "So that's why I'm here."
Perry didn't just lend her presence to the event, she also sang live for those who came out to the annual fundraiser. Donning a frilly, light-pink gown, Perry played a short set, which included her hits "Roar," "Teenage Dream," "Firework" and "Dark Horse."
After wrapping up her performance with an emotional rendition of "Somewhere Over the Rainbow," Perry was presented with a bouquet of flowers by a young boy named Caiden Moran, who is deaf. Perry gave Caiden a kiss on the cheek and used sign language to say, "I love you."
Perry, Barrymore and Gad were among many big-name guests at the event, which also included Jessica Capshaw, Jamie Lee Curtis, Katharine McPhee, Eric Stonestreet, Holly Robinson Peete and Luc Robitaille, among others.
Back in June, Perry traveled to Vietnam in her role as a UNICEF Goodwill Ambassador, where she fought to raise awareness about the plight of economically disadvantaged children who are left behind even as the country's economy grows. Check out the video below for more on the singer's "heartbreaking" goodwill mission.