Hewitt, a U.S. Open and Wimbledon singles champion, officially retired from top-level tennis after his home grand slam in 2016, where he also played doubles with Groth. He did, however, play doubles during the Davis Cup and Wimbledon last year.
"It's going to be a bit of fun. That's what the Australian Open is about," Hewitt told News Corp Australia on Friday.
"I'm going to really enjoy it. We've been hitting a lot of balls, hitting every day, and we're not just going out there making up the numbers.
"We want to give it a fair crack."
Groth, who is retiring after the season-opening grand slam and is hoping for a wildcard for the singles draw, will also play mixed doubles with Sam Stosur.
"Its something Lleyton and I have talked about and it's perfect for me," Groth said.
"I was there when Rusty retired in 2016 and its great that he'll be there with me when I bow out. He's not just someone I know through tennis, he's a great mate."
(Reporting by Greg Stutchbury in Wellington; Editing by Toby Davis)
