With the Scot celebrating a landmark occasion, we asked supporters to join us in sending our best wishes to our legendary former manager.
More than 10,000 of you have already got involved, with messages coming in from more than 150 different countries across the globe. Some have recalled a chance meeting with the boss, others a touching letter he sent them, others simply their favourite memory of the Sir Alex Ferguson era at United, and many of you explained how the Govan-born great has acted as a source of inspiration with his determination, values and unparalleled success.
Throughout today, tributes will be paid to Sir Alex from across the football world.