Pop star Michael Jackson sings the "Earth Song" during the World Music Awards ceremony at the Sporting Club in Monte Carlo in this May 8, 1996 file photo.[Photo/Agencies]

Michael Jackson was unconscious backstage before a London news conference for his "This Is It" concert series, and he appeared drunk during the announcement itself, an attorney said in court on Monday.

The revelation came during a hearing in the involuntary manslaughter trial of Jackson's former physician, Dr. Conrad Murray, a day before opening arguments are scheduled to start.

Murray's defense lawyers wanted a video of the news conference shown to jurors in the trial, but the judge in the case ruled against it. The defense team is widely expected to argue Jackson was a drug addict whose habits led to his death.

Nareg Gourjian, an attorney for Murray, said in court on Monday that the "Thriller" singer's March 2009 news conference in London to announce a series of concerts in the city began 90 minutes late because "Jackson was unconscious on the sofa."

Gourjian said Jackson appeared "hung over," citing the chief executive of concert promoter AEG Live which was organizing the shows. He argued it was "readily apparent from watching the video that Mr. Jackson was under the influence."

But Los Angeles Superior Court Judge Michael Pastor, who is presiding over Murray's trial, ruled against showing the tape to jurors. Pastor said the video was irrelevant because it occurred months before Jackson died.

Pastor also denied a request by prosecutors to present evidence that investigators sought four times to contact Murray, after the doctor met with Los Angeles police detectives two days following Jackson's death.

The involuntary manslaughter case against Murray stems from Jackson's death on June 25, 2009, at age 50. Medical examiners determined Jackson died of an overdose of the powerful anesthetic propofol and sedatives.

Prosecutors said Murray caused Jackson's death by giving him propofol as a sleep aid at the singer's Los Angeles mansion and not properly monitoring him.

Murray has pleaded not guilty, and his defense attorneys are expected to seek to show Jackson administered a fatal dose himself while Murray was out of the room.

Attorneys for both sides are scheduled to begin opening arguments on Tuesday before a jury of seven men and five women. Murray faces a maximum of four years in prison if convicted.