The club have announced two pre-season matches against the Italian giants - against Roma on 26 July at Denver's Sports Authority Field and Inter on 29 July at Washington DC's FedEx Field.
Irwin was in Washington DC to launch the matches and is expecting two exciting games in July.
"Pre-season is about getting fit, getting as much training under your belt as possible and playing some tough games, and that's what we've got," the United legend told ManUtd.com.
"The facilities are second to none in the States and we'll be able to take advantage of those, and having such quality opposition to play against is fantastic. They are both great teams with great history and it'll be a test, but that's what pre-season is all about."