It explodes into one big, cut-loose kind of celebration

Ceremony producer Don Mischer

Organisers said the ceremony at the Rice-Eccles Olympic Stadium on Sunday at 1800 local time (0100 GMT Monday) was destined to be a fun rather than formal occasion.

BBC correspondent Matt McGrath said demand for tickets was high, with touts charging $1,000 (�700) a time.

Charlotte performed a duet with young American operatic star Josh Groban on whose latest CD she appears.

Sense of unity

Emmy-award winning producer Don Mischer said the event was to be more informal than the opening ceremony which featured Sting, Rita Coolidge, LeAnn Rimes, the Dixie Chicks and cellist Yo-Yo Ma.

He said the closing celebration reflected the sense of unity felt by athletes and performers alike in the light of 11 September and the war on terrorism.

"It explodes into one big, cut-loose kind of celebration," he said.

Charlotte met President Clinton in 1999

"There's no doubt the mood has changed. It's almost as if the Olympics are more important now than they ever could have been."

It has been a busy year for Charlotte Church who celebrated her 16th birthday last week.

On Monday she treated more than 100 of her friends to a secret five-hour party at a Cardiff nightclub.

The singer then flew to America in preparation for her Olympic engagement.

She spent her birthday night on Thursday with two girl friends at the trendy Moonba nightspot in Los Angeles.

Charlotte has performed in America several times since she was discovered on a British television show at the age of 12.

Charlotte: Her youthful image

She sang for former US President Bill Clinton at the White House in 1999 and at the inauguration of his successor George W Bush in January 2001.

But in November 2001 there was controversy in the US over an interview she gave to a British newspaper.

In the Sunday Times article, she appeared to criticise the hero status accorded to New York firefighters clearing up the debris of the World Trade Centre after 11 September.

The singer issued a statement of apology after the New York Post attacked her "devilish attitude".

She said her comments had been "distorted and misrepresented".