Jackson announced his comeback shows in March this year.
More tickets for Michael Jackson's This Is It concerts at London's O2 arena are to go on sale on Wednesday.
The "limited" number of extra seats - thought to be hundreds per show - had been held back as production logistics were worked out.
Fans who have registered on his website will be entered into a lottery system in order to buy the tickets.
The first 750,000 tickets for the 50-show run were snapped up when they went on sale in March.
The pop superstar will take to the stage for his first show on 13 July - five days later than planned.
Four initial shows were rescheduled last month when promoters AEG Live said the singer needed more time for dress rehearsals.