The forward pair spent eight years together at Old Trafford, with Nani's Premier League debut coming in August 2007 as a substitute for the ex-England captain.
The two ex-Red Devils will now clash on opposite sides of the field in Florida, and Nani is looking forward to talking with his friend and rival.
"We will meet here in Orlando, it’s a long time since I've seen him, it will be a good time to catch up, and talk a little bit," the Portuguese star explained to CNN.
"We will enjoy seeing each other, hopefully put on a good show for the fans, challenge each other and at the end we can sit and chill out a little bit."
A newcomer to the United States, Nani is enjoying his new challenge at the age of 32 and states that he has been overwhelmed by the welcome he has received.
"Ever since the day I played my first minutes for Orlando at home in from of our supporters, they have been fantastic," he added.
"We got a point in that game when it was very difficult game for us, we were losing, at the end it was good, and since then a great feeling for me.
"So far, the stadiums have been full. It’s a great feeling as a football player, you like this kind of environment, you like to see the stadium full of passionate supporters. As a player you need that, you need that to give the big motivation, to show to the fans your quality of football and to enjoy the game on the pitch.
"When you have a full stadium and great atmosphere you want always to enjoy."
Orlando currently lie sixth in MLS' Eastern Conference, having started the season with two draws, a defeat and a victory.
Rooney's D.C. United occupy second having played a game fewer, with the United legend netting a hat-trick in his team's last outing, a 5-0 thrashing of Real Salt Lake.