Jackson has delayed the opening four dates of his residency
A promoter is suing Michael Jackson for $40m (£24.4m) for allegedly breaching a contract to play a reunion concert in the US with other family members.
Allgood Entertainment claims it made a deal in November with Jackson's then-manager to produce the gig this summer.
It says the deal called for Jackson not to perform elsewhere before the event or for at least three months after it.
He will play 50 dates at London's O2 arena from July. Promoter AEG will not comment while Jackson was unavailable.
Allgood say the concert would have involved the singer, sister Janet, and the other members of The Jackson 5 - Marlon, Jackie, Tito and Jermaine.
In legal papers filed in Manhattan, Allgood accuse the singer and manager Frank DiLeo of breaking the contract by signing up to do the O2 shows.
AEG is also named in the papers.
The papers add that AEG knew of the agreement between AllGood, DiLeo and Jackson, "but due to their dominance and power in the live performance industry, coerced and/or induced DiLeo and Jackson to disregard the agreements with AllGood and to work with it instead".
"We've given Michael Jackson and AEG every opportunity, publicly and privately, to resolve this matter and to date we have not heard from anyone," said Patrick Allocco, a managing partner for Allgood.
Allgood's lawyer Ira Meyerowitz said the company was not looking to stop Jackson from performing at the O2.
"What we're looking for is for our clients to be involved in the London concerts or be compensated for agreements they entered into," he said.
A spokesman for AEG said the company would not comment on pending litigation.