The 37-year-old will return to the court in Portugal for the Estoril Open.
Organisers from the event tweeted: “We have a wild card, we have the ex-world-number-one Lleyton Hewitt ... Who will break from ‘retirement’ to play at the Millennium Estoril Open alongside countryman Alex de Minaur."
The tennis great retired from playing professionally in 2016 but returned to play at the Davis Cup, at Wimbledon and alongside Sam Groth at the Australian Open last year.
Hewitt has two grand slam titles under his belt, including winning the US Open in 2001 and Wimbledon in 2002.
De Minaur is currently ranked 114th in the world and is tipped to be the next big thing in Aussie tennis.