Simpson, 27, will perform along with Christine Anu, singer-songwriter Zipporah Corser-Anu, Mike Brady AM and international pop star Katy Perry as a part of the pre-game entertainment. 

The musician and athlete decided to leave music behind to pursue professional swimming in 2019 but is returning to the stage after failing to qualify for the Paris Olympics. 

"I'm stoked beyond words to have been asked to sing the biggest national anthem of the year at the AFL grand final," Simpson said in a statement.

"It's a special and timely opportunity for me to step back on stage for the first time after my sporting career.

"As an Australian, it's one of the greatest honours, and I hope I can deliver something that everyone can sing along to and share in the pride of being a member of this beautiful country."

AFL CEO Andrew Dillon said the league was proud to include homegrown talent in the pre-game entertainment. 

"The AFL is proud to have a host of talented Australian artists as part of our Telstra pre-game entertainment as we celebrate the end of another outstanding season," Dillon said.

"Cody, Christine, Zipporah and Mike are no strangers to performing on some of the biggest stages and are ready to put on a spectacular show at the 'G on the last Saturday in September.

"I'd like to thank Telstra for its ongoing support of our pre-game entertainment and look forward to seeing our Aussie artists, together with international icon Katy Perry, perform in front of the 100,000 fans in-stadium and the millions watching at home."

Simpson has previously performed at the 2022 AFLW Grand Final.