Top DJs Kyle Sandilands and Jackie O are moving to a new station after running the breakfast show on Sydney's 2DayFm since 2005.
After months of speculation over who would replace them, radio bosses have announced Brown will sit on a panel of four new hosts.
She will broadcast the show alongside actress Sophie Monk, and long-running DJs Merrick Watts and Jules Lund.
Brown will split her time between the U.S. and Australia to manage the job.
She says, "I'm so excited, this is going to be one hell of a roller-coaster ride. I just can't wait, to be honest."
Brown has appeared as a judge on Australia's The X Factor as well as working as a presenter on the country's version of Dancing with the Stars. She currently sits on the panel of America's Got Talent.