Sarah Brightman in this file photo undated. [Agencies]

BEIJING - British singer Sarah Brightman and China's Liu Huan will sing at Friday's opening ceremony for the Olympic Games, organisers said on Wednesday.

Brightman, best known for her appearances in shows in London's West End including "The Phantom of the Opera", will sing with Liu Huan a specially commissioned "theme song" which will make up part of the three and a half hour ceremony.

The entertainment will begin at 5:45 p.m. and the ceremony proper, featuring 15,000 participants, will follow from 8 p.m. for three and a half hours.

Zhang Heping, director of Opening and Closing Ceremonies Department of the local organising committee (BOCOG), said the ceremony would feature performing arts which "showcase the ancient and long history of the Chinese nation" as well as reflecting modern day China.

After the theme song of the ceremony there will be an address by officials and then the entry of the Olympic flag.

The athletes will then march into the stadium with their own flags -- nations will enter in Chinese alphabetical order, said Zhang.

The ceremony will close with the lighting of the Olympic flame but Zhang gave no clue as to the identity of the final torch bearer.

"For the lighting of the flame, the last torch bearer, this is the most secretive part and will be revealed at the very last moment," said Zhang, adding that the person had been chosen taking into account their "sporting achievement" and "social influence".

Zhang said he hoped there would no athletes using the occasion for protests.

"(We) hope and believe the athletes in the Olympic Games know they should not link the Olympic Games with politics," said Zhang.

"It would run against the charter of the Olympics and the spirit of the Olympic movement," he added.

The firework show, which is part of the opening ceremony, will feature the firing of 29,000 shells -- 15,000 inside the stadium and 14,000 in the vicinity.