The 'Happy' hitmaker knew the King of Pop for several years before he died of acute Propofol intoxication in 2009 and had penned some tracks for the star but they were rejected by his team and ended up being given to Justin Timberlake for his debut solo album 'Justified' - and Pharrell was shocked when the 'Billie Jean' singer later sang them to him and he had to confess they were originally destined for him.
He said: ''I did eight songs for him that never made it to him, that ended up on Justin's record.
''Later he sang me all those songs and told me they should have been his and I told him they were for him.''
The 'Get Lucky' star also laughed off comparisons between himself and the late 'Thriller' singer.
He told News.com.au: ''Well, there's no comparison between me and Michael Jackson. He is the King of Pop, an incredible dancer, an incredible writer, incredible visionary, he changed the world in so many ways.
''I am just a fan who has been given the opportunity to make music.''
All I Want For Christmas is widely regarded as one of the best festive tunes every year
Pearl Jam announced 14 dates in the UK and Europe in June and July 2018.