London - US popstar Michael Jackson will make a "special announcement" in London this week which is widely expected to focus on the launch of a comeback tour in Britain this summer.

Celena Aponte of London agents The Outside Organization said Jackson would give a news conference at the O2 Arena concert venue in London's docklands Thursday.

While she would not explicitly confirm any details of the impending announcement, speculation grew to fever-pitch Tuesday that the King of Pop would reveal his plans for a string of comeback concerts in Britain.

The pop icon is widely expected to play a residency at the 20,000-capacity O2 Arena over the summer.

Jackson, 50, who ruled the pop world during the 1980s, has in recent years appeared more reclusive amid concerns over his health.

He last visited London in 2006 for the World Music Awards. (dpa)