Lleyton Hewitt will come out of retirement to play doubles at the ATP Estoril tournament in Portugal with emerging Australian talent Alex de Minaur.
"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," tournament organisers tweeted.
Hewit, Australia's Davis Cup captain, retired from professional tennis in 2016, but made a cameo appearance alongside Sam Groth at the Australian Open, where the duo made the quarterfinals.
The youngest man to be ranked world number 1 in singles, Hewitt won the 2001 US Open and 2002 Wimbledon titles just a few years after his new doubles partner was born.
De Minaur, 19, turned professional in 2015, and is ranked 114 in the world.
The youngster made his Davis Cup debut in 2018, but lost his singles rubber against German world number 5 Alexander Zverev in five sets.
Earlier in the season he defeated Canadian Milos Raonic at the Brisbane International before being defeated in the semifinal by American Ryan Harrison.