Michael Jackson has delayed the opening four nights of his residency at London's O2 arena.

The first show of the “This Is It” tour on July 8 has been pushed back by five nights. The other dates have gone back to March 2010.

An email from Ticketmaster and promoter AEG Live  states: "Due to the sheer magnitude of the “This Is It” concerts at the O2 Arena promoters and producers AEG Live and Kenny Ortega, Michael’s directorial partner and creative collaborator have elected to move back a few of the opening shows in order to meet the challenges presented by such a massive and technically complex show.

"We wanted to ensure that all of Michael's fans attending the concerts get the same quality in staging and level of entertainment.

"It is AEG Live's sincere hope that those lucky enough to have purchased tickets will have enough time to change their personal schedules and travel plans if they are coming from outside of London.

"We do not want anyone to miss this once-in-a-lifetime experience. We understand the inconvenience this may have caused and for this reason we have secured some excellent hotel deals for Michael Jackson fans traveling to London on these rescheduled dates."

Full refunds are available to those who can't make the shows. There is no explanation for the delay.

Here's the changed Michael Jackson dates:

8th July will take place on 13th July 2009
10th July will be moved to 1st March 2010
12th July will be moved to 3rd March 2010
14th July will be moved to 6th March 2010