The now-England coach spent his entire career with United, making a total of 602 appearances for the club until his retirement in February 2011.
Despite being a one-team man, the 37-year-old has confessed that he has always been impressed by the way that Bayern function as a club.
"I was asked which club I would have liked to have played for if I had ever moved abroad and left Manchester United. My first instinctive reaction was Bayern Munich, followed by Juventus," he wrote in the Daily Mail. "The Bundesliga club had always impressed me when I played against them with Manchester United. It was the little details that told you everything about the professionalism of the club. Like the team bus.
"They would always have their team bus, wherever they went. Most clubs, when they fly abroad, borrow a bus to get them from the airport to the hotel and stadium. Not Bayern Munich.
"Their bus driver would set off three or four days before the match, driving across countries, catching ferries, so that when the team arrived, their bus would be at the airport waiting for them. It was that attention to detail which so impressed me."
The German club will be coached by former Barcelona manager Pep Guardiola next season.