Eilish will be performing her new single "Therefore I Am" virtually from Los Angeles. Smith will perform remotely from Abbey Road Studios in London.
"Australia has always held such a special place in my heart, and I am so honored to be a part of this year's ARIA Awards! I'll be crossing live from London with a very special performance for you all. I can't wait to see you soon!" Smith said in a statement.
Sia, Tame Impala, Sampa The Great, Lime Cordiale and Amy Shark are also scheduled to perform.
Delta Goodrem, a 12-time ARIA Awards winner, is hosting the ceremony. The ARIA Awards showcase the achievements of the Australian music industry.
The awards show will be held at the Star Event Centre in Sydney and broadcast around Australia on the Nine Network. Performances will stream on YouTube.