Teenage singer Charlotte Church had to sit a GCSE exam before the crack of dawn - because she was performing in America.

Strict rules to prevent cheating meant the 16-year-old star had to start the geography paper the same time as her classmates in Cardiff.

I'm so nervous about the exams ... all my friends think I'll be able to cheat because I'm sitting them on my own

Charlotte Church

As a result, Charlotte had to take the test at the British Embassy in Washington DC at 0400 local time on Monday (0900 BST) under the watchful eye of an independent invigilator.

Charlotte had time for breakfast before sitting her English Literature paper at 0800 local time - for her friends it was 1300 BST.

Speaking beforehand, Charlotte said: "I'm so nervous about the exams - it will be horrible to do them on my own."

"All my friends think I'll be able to cheat because I'm sitting them on my own out here.

Charlotte was singing at a concert in Washington

The singer had no time for last minute swotting on Sunday night - she was performing at a concert to remember the victims of the terrorist attacks of 11 September.

Charlotte had flown to America on Thursday after sitting her music GCSE with her classmates.

She was due to return home on Tuesday to catch up with her schoolmates for the rest of her ten GCSE exams.

Strict regulations

A spokesman for Sony, Charlotte's record company, said: "She had to sit the exams at the same time as her classmates because of the rules.

"It shows how keen she was to perform at the memorial concert."

Charlotte joined Catherine Zeta Jones on Ian Botham's charity walk

The teenage star was one of 10,000 pupils sitting the geography exam and 60,000 doing the English Literature paper set by the Welsh Joint Education Committee.

Derek Stockley, director of examinations, said Charlotte's absence was not a major problem.

"Whenever a pupil sits an exam away from a main centre then we do everything we can to make sure they take it in fair conditions," he said.

"We speak to the invigilator and send the papers under strict security.

"Every candidate is given an equal chance to succeed."

In April, Charlotte helped cricket legend Ian Botham raise �850,000 by joining the final leg of his charity walk around Wales in aid of a the Noah's Ark children's hospital appeal.