Wearing his trademark sunglasses and a silver-embroidered black military-style jacket, the King of Pop said his series of shows in July will be his "final curtain call" in the British capital.
"This is it," Jackson said in a brief statement punctuated by the squeals of fans who gathered inside the massive O2 Arena in southeast London on Thursday. "And when I say this is it, I mean this is it."
Although Jackson said the shows would be his last in London, his statement left the door open for further concerts elsewhere. Promoter AEG Live told the BBC the shows might be part of a bigger, final world tour.
An hour and a half late, Jackson appeared at the O2 - where the series of 10 concerts are due to be staged this summer - to announce the gigs.
More than 300 journalists had been marshaled to capture the event, even though news of the concerts had leaked out to the media days before. A telegenic army of screaming fans was there to greet their star - although many in the crowd said they were there to catch a live show due to play shortly after the announcement.
The hours spent waiting frayed some tempers and a few fans shouted obscenities at journalists being escorted in ahead of them for the announcement. But most were just happy to catch a glimpse of Jackson.
"I've always been a fan ever since I was really little - his music and the way he moves," said 21-year-old student Shellie Watson. When asked if Jackson - who was almost Watson's age when he released "Thriller" in 1982 - still had star power, she said "100 percent."
"Thriller" is still the best-selling album of all time, but Jackson - who has sold more than 750 million albums and won 13 Grammys - has not performed a major concert since 2001.
Tickets priced between 50 pounds and 75 pounds ($70 and $105), are expected to sell quickly for the shows, despite concerns the 50-year-old star may not be up for a return to the spotlight.
The King of Pop has been plagued by financial, legal, and medical woes for years, and a previous attempt to relaunch Jackson's career collapsed amid reports of ill health and court action.
Jackson has appeared in public rarely since being acquitted of child molestation in California in 2005, and he has struggled to pay his debts - last year, he was forced to give up the deed to Neverland, his 2,500-acre (1,000 hectare) ranch and miniature amusement park in California.
On Wednesday, Jackson launched a lawsuit against an auction house to stop the scheduled sale of more than 2,000 personal items from Neverland, including platinum and gold records, a customized Harley Davidson and a Rolls Royce limousine.
The O2 has become a venue of choice for big-name acts and comeback performers. Britney Spears is due to play there for eight nights in June, Prince did a 21-day series of shows at the arena in 2007, and Led Zeppelin played a one-off reunion gig there the same year.
The concerts - possibly followed by other gigs and a 3-D movie based on "Thriller" - could end up netting Jackson more than $400 million, Randy Phillips, the chief executive of AEG Live, was quoted by the BBC as saying.
That would be welcome news for Jackson, who has been entangled in lawsuits for years, but whether he is up for a world tour remains to be seen. Jackson's recent work has been uneven: His last live performance in Britain was at the 2006 World Music Awards, but only managed a few lines of "We Are the World" before leaving the stage.
A video of Jackson trying to record a new single, shown at a British court last year when Jackson was being sued for breach of contract, showed him struggling to keep up his powerful vocals.
Rebecca Kellner, 17, said it didn't matter really matter how Jackson sang - the fans would come.
"He's not the greatest singer and maybe not the greatest person," she said. "But he's Michael."
(This version CORRECTS to 'Rebecca' sted 'Rebbecca'. )