Michael, whose birth name is George Panayiotou, appeared confused when entering his plea, claiming he was guilty due to "tiredness and prescribed drugs".

George, from north London, was arrested in Cricklewood last year after motorists reported a car obstructing the road at traffic lights.

The singer’s sentencing was adjourned to enable more blood tests to be carried out.

George told the court he was "very ashamed" of his drug-driving charge and that he had done something "very stupid".

He took the unusual step of speaking directly to the judge in open court today.

First he thanked District Judge Katherine Marshall. He said: "I have only been aware for the last 15 minutes that this was a possibility to address you in an open court.

"I just want to be as brief as possible.

"There are two reasons we are here today.

"I did something very stupid and I am very ashamed since doing it.

"I’m not used to defending myself in a position where I am ashamed of something.

"If I had known the day after the charge was brought the legal option of accepting a punishment without taking responsibility for something I felt I was not guilty to I could have saved everyone here a lot of time and trouble."

George adds court date to tour - April 25 2007
George Michael is set to appear in court the day before he performs at Wembley Stadium following a ruling by a district judge.

The trial of the 43-year-old former Wham! star has been listed to start on May 8, followed by the dates of May 30, May 31 and June 8, after a preliminary hearing at Brent Magistrates’ Court in north west London.

The star, whose birth name is George Panayiotou, will face a charge of driving while unfit through drugs and an allegation of being in charge of a vehicle while unfit through drugs.

It was announced last month that the singer will play the first concert at the new Wembley Stadium on June 9, as part of his British and European stadium tour which starts in May.

District Judge Katherine Marshall rejected an application for the star to be allowed to be absent throughout the trial.

She said she wanted him to be in court on May 8 and she would be willing, if he did not wish to remain at the trial, to bail him to reappear on the final day.

The judge noted: "He is around in the area because I believe he is appearing at Wembley Stadium. I do not think he will have any difficulty in being here on June 8."

Michael concert a first for Wembley - Mar 5 2007
Popstar George Michael will play the first concert at the new Wembley Stadium.

The singer, who performed on a number of occasions at the old Wembley Stadium, will take to the stage at the new venue on June 9 as part of his British and European stadium tour.

The tour kicks off at Aarhus Stadium in Denmark on May 18 and will visit Manchester, Glasgow, Plymouth and Norwich as well as France, Italy, Belgium, Germany, Denmark, Slovakia, the Czech Republic, Sweden, Holland and Hungary.

Michael will be the first artist to play at the 90,000 capacity venue, the opening of which has been beset by repeated delays and financial wrangling.