The eccentric singer, who seemed to be suffering from stage fright, struggled to hit the high notes and looked uncomfortable throughout his performance of 'We Are The World'.
The singer only delivered a handful of lines before being booed off stage.
Jackson was accompanied by a children's gospel choir who sang most of the song before the 48-year-old even made it onstage.
When he did eventually appear, his loyal fans - some of whom had paid £500 to see him for the first time in the UK in almost a decade - were left disappointed as Jackson managed to only sing a few lines of the chorus, instead preferring to wave to the crowd and shout "I love you!" One fan said: "It was such an anti-climax. All night the crowd were cheering his named and we waited for ages before he finally came on stage to sing.
"The choir sang the whole song, I could only hear him mumble a few lines. He looked lost and didn't even attempt to try and dance. Everyone thought he would sing 'Thriller'. So much for the return of the King of Pop, it was embarrassing." Jackson, dressed in his trademark black, threw his sequin jacket into the crowd, posed with the choir and left the stage - after only four minutes.
Fans had been expecting Jackson to perform his seminal hit 'Thriller', but that was performed earlier in the night by new US star Chris Brown.
Brown - dressed in a tribute red and black leather jacket - was joined by a troop of 'zombie' dancers.
Jackson was given the Diamond Award which honours artists who have sold more than 100 million records.
Introducing Jackson to the stage, Beyoncé Knowles gushed: "Tonight we are celebrating 25 years of 'Thriller'," referring to his hit album. If it wasn' t for Michael Jackson I would never have ever performed. I love you, we all love you." As Jackson accepted the award, he thanked his fans and family for remaining loyal.
He said: "I am greatly humbled by this award. It was my dream that 'Thriller ' would be the biggest-selling album ever and God has answered my prayers.
"So many people have loved me and stood by me. I thank my children for their unconditional support and love. I also thank my mom and dad, my brothers and my sisters. I love all my fans from the bottom of my heart." Jackson's appearance at London's Earl Court had sparked a frenzy among fans, with hundreds waiting outside the venue for hours hoping to catch a glimpse of their idol.
Winners on the night included, Madonna who was awarded World's Best Pop Artist, Nelly Furtado for World's Best Pop/Rock Artist and Beyoncé for World 's Best R 'n' B Artist.
Performances by Beyoncé, Nelly Furtado and Andrea Bocelli were the highlights of the evening, and the ceremony was presented by Lindsay Lohan.


2006 World Music Awards Full list of winners:

World's Best Pop Artist - Madonna
World's Best Pop/Rock Artist - Nelly Furtado
World's Best Rock Group - Nickelback
World's Best R'n'B Artist - Beyoncé
World's Best Rap/ Hip Hop Artist - Kanye West
World's Best Latin Artist - Shakira
World's Best DJ - Bob Sinclair
World's Best New Artist - James Blunt
Diamond Award - Michael Jackson
Best-Selling Arabic Artist - Elissa
Best-Selling British Artist - James Blunt
Best-Selling German Artist - Tokio Hotel
Best-Selling Irish Artist - Enya
Best-Selling Italian Artist - Andrea Bocelli
Best-Selling Russian Artist - Dima Bilan