United will be back on Australian soil for the first time since 1999, they will play a pre-season tour in preparation for the 13/14 season.
United will face the All Stars in the ANZ Stadium on 20th July.
United chief executive David Gill told the club's official website: "We are delighted to accept the invitation from the New South Wales Government and the Football Federation Australia to visit one of the world's truly great cities."
He added: "There are three main reasons we go on pre-season tour. First and foremost is the team's preparation for the season ahead. But the tour also allows us to engage with our global fan base and network of commercial partners.
"It has been a while since we last visited Sydney and we are looking forward to renewing our relationship with our loyal and enthusiastic Australian fans."