The Lancaster County native announced the upcoming appearance on her blog this morning. The episode was filmed in Baltimore and will air Aug. 26, according to an episode list posted on MSN.com.
No further details are being released right now, Beiler spokesman Gentry Austin said. ABC will reveal more about the show as the air date nears, he said.
"Secret Millionaire" follows self-made millionaires "as they keep their true identities hidden while living in some of the country's most impoverished neighborhoods," according to ABC promotional materials.
After a week of living on a stringent budget and getting to know the community, each millionaire reveals himself or herself and makes a six-figure donation to an organization or people they found most deserving of assistance.
The show is modeled on a British original. An American version ran on Fox for one season; ABC began broadcasting episodes last year. The show airs at 8 p.m. Sundays.
Beiler and her husband, Jonas, founded Auntie Anne's pretzels in the late 1980s; the franchise has since grown to more than 1,200 stores in more than 20 countries, according to the company website. Atlanta-based Roark Capital Group acquired the company in 2010.