The 50-year-old announced last week that he would return to the stage 12 years after his last series of concerts, although the original commitment was to 10 gigs at London’s O2 Arena.
That has now expanded to 50, ending on February 24, 2010.
Hundreds of thousands of tickets went on sale to registered fans earlier in the week, and ahead of Friday’s general release hundreds of people queued at the O2 Arena to ensure they made it to the eagerly-awaited shows.
Many had camped overnight for the privilege.
Jackson has been a virtual recluse since his acquittal on child abuse charges in a 2005 trial and he has not recorded an album of new music since "Invincible" in 2001.
But he is still the "King of Pop" to legions of followers despite his sometimes bizarre behavior and appearance. He has sold around 750 million records, won 13 Grammys and is regarded as one of the biggest pop acts of all time.